Wastewater
 

	New Connections
	Pricing
	Education
	Locating Pipelines
	Septic Tanks
	Alternative Systems
	Private Drains Information - Who owns that pipe?
	Assessment of Water and Sanitary Services
	Preventing wastewater overflows

Wastewater is used water and waste from our homes and workplaces. Also known as "sewage", wastewater is 99% water. The other 1% consists of:

• organic matter such as human waste and food scraps
• oil and grease
• heavy metals such as silver, lead, zinc and copper
• debris such as sand, grit, wood and plastic
• bacteria and viruses that can make people ill
• nutrients such as nitrogen and phosphorus that sound healthy but, in reality, can harm our harbours and waterways. Nutrients can deplete oxygen, create excessive plant growth, cause fish to die and result in toxic algal blooms.

Every time you flush the toilet, pull the plug from your sink or have a shower, the wastewater drains into a sewer pipe on your property. If you are part of the reticulated system in Waitakere City, that pipe will then connect you to the local sewer network which is owned and operated by the Council. These pipes then carry the wastewater to a main bulk sewer pipe. In Waitakere City, this main pipe is called the Western Interceptor, which transports our wastewater to the Mangere Wastewater Treatment Plant managed by Watercare Services Ltd.

About 286 million litres of treated wastewater is released into the Manukau Harbour daily from the Mangere plant. This is the equivalent of over one petrol tanker every three seconds!

Why we can no longer ignore our wastewater problem

• The population in the Auckland region is predicted to double in the next 50 to 60 years which will place the existing wastewater network under pressure.
• The Western Interceptor pipe will be at capacity by the year 2050.
• Raw sewage overflows into our harbours during heavy rain. This is caused by stormwater leaking into ageing sewer pipes. This is no longer acceptable if we want to swim at our beaches and collect shellfish without risking our health.

What is being done about it?

Wastewater management is both a regional and local responsibility.  Wastewater management is both a regional and local responsibility. Sixty years ago, raw sewage was pumped directly into our harbours. Since that time, public expectations about environmental standards have radically changed.  Keeping our harbours clean has become a priority.

In April 2003 the new Mangere plant was officially opened.  At a cost of $450 million, the new plant doesn't increase capacity but improved the treatment process. The new treatment plant reduces the treatment cycle for wastewater from 21 days to 13 hours and provides bathing water quality discharge into the harbour. New land-based technology has allowed 500 hectares of oxidation ponds to return to the Manukau harbour and restoration of 13km of shoreline.

EcoWater is currently working on wassa - an Assessment of Water & Sanitary Services to look at the best ways to sustainably manage our three waters.

We can't afford to waste our water

How does this affect us on a personal level? Our modern lifestyle includes dishwashers, high pressure showers, spa pools... in other words, we use huge amounts of water that end up back in the environment as wastewater. Reducing the amount of wastewater we create reduces the pressure on the wastewater network.  For more information on water saving tips view water saving tips.  Or contact us to find out how to read your water meter. This will help you become aware of your water consumption. You'll also be able to find out if your home or business premises have sprung any invisible leaks that are costing you money and wasting precious water.

Solving wastewater problems

The Auckland region faces major decisions regarding the future management of wastewater to cope with rapid population growth and an ageing infrastructure.
EcoWater is committed to managing wastewater in ways which will:

• protect public health
• enhance environmental values
• use financial resources wisely

You can help to ensure the wastewater system runs efficiently by checking that your house roof downpipes are not being fed into gully traps but rather into a stormwater drain. Proper installation will ensure that your stormwater will not get into the sewer to cause overflows during times of heavy rain.

New Wastewater Drainage Connections

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Minor Engineering & Works near WCC's existing Networks  (Size 368K)

Pricing

Note: You will need to have Adobe Acrobat Reader installed on your computer in order to view and print this document.  For help opening PDF files or tips on copying information see Helpful Tips.

Locating Pipelines

This service entails locating buried service pipes and may attract a charge. Please contact our Call Centre for more details.

Find out who is responsible for maintaining pipes and fixing water supply and drainage faults.

Septic Tanks

Caring for your Wastewater System and the Environment

Out of sight, but not out of mind.  
Your house, like any other in rural Waitakere City, has a wastewater system to treat domestic wastewater (wastewater originating from household activities, such as toilets, kitchens and bathrooms including shower, bath, washbasin and laundries). Properly installed and maintained, your wastewater system will protect the health of your family and the environment. Forget it and the system is likely to clog up, pollute the environment, put you and your neighbours health at risk and be expensive to repair.

The Waitakere City Council has prepared this information so you can operate an efficient and environmentally friendly system.

Owners responsibility - wastewater disposal system

To assist in the efficient operation of your wastewater system the Council provides a regular pump out (frequency depends on the type of system you have) and checks the operation of your wastewater system, however, it remains the responsibility of the owner to ensure the efficient operation of their wastewater system.  Every property owner with a wastewater disposal system must ensure the system operates to a safe and satisfactory standard.  Nuisances such as offensive odours, effluent seepage and other forms of environmental pollution caused by system failure must be stopped.  It is the responsibility of the owner to upgrade, repair or replace the system and ensure any nuisances stop.

The Wastewater System - what is it?

A typical wastewater system is shown in diagram 1.

Diagram 1: Conventional Wastewater System Layout

There are a number of different types of wastewater systems and all work according to the same basic rules.  Wastewater produced by your household, flows down the drains to the septic tank.  In the septic tank solids settle out and the breakdown of wastewater takes place.  From here the partially treated wastewater (termed effluent), flows into a disposal field via pipes.  Natural processes in the soil (disposal field) absorb and evaporate the effluent over time.

What does the septic tank do?

The job of the septic tank is to pre-treat domestic wastewater before it enters the disposal field.  Three processes take place within the tank:

1. Wastewater separation
Solids settle to the bottom of the tank and form a layer of sludge.  Light wastes, such as fats and grease, float to the surface forming a scum layer. The majority of the wastewater forms a central fluid column (see diagram 2).

2. Wastewater pre-treatment
Bacteria in the septic tank feed on and break down the bacteria and nutrients in the wastewater. This is an anaerobic process (continues in the absence of air) which causes an offensive odour, however the scum layer on top prevents most of this odour from escaping.

3. Wastewater flow
Incoming wastewater flow forces pre-treated effluent out of the septic tank and into the disposal field.

Locating your septic tank

Your septic tank should be located as high in the ground as possible, if the septic tank is not readily accessible, a manhole should be provided to enable maintenance. This eliminates groundwater getting into the septic tank and also makes pump-outs easier. You can usually find the septic tank by looking for the fresh air inlet (the mushroom) in your lawn or by locating the lid.  If you can't see the lid, then look for a mound or dip by the air vent, or a place where the grass is thinner than anywhere else. It's a good idea for future reference, to draw a simple sketch plan of your property layout showing the house and wastewater system. The picture should include your house, septic tank, disposal field, pipes and property boundary.

Diagram 2: Conventional Septic Tank

The Disposal Field where it all goes

When the wastewater leaves the septic tank, it is only partially treated and further treatment of the effluent takes place in the disposal field (irrigation).

Types of disposal fields

Conventional trickle fed soakage trenches
Effluent trickles out of the septic tank and into the soakage trenches and through scoria into the ground. This is the most common type of disposal field. It is used on reasonably flat sections where water can readily soak into the ground.

Evapo-Transpiration Systems (ETS)
i. Standard ETS Systems (non-dose loaded) use sub-surface soakage and evapo-transpiration (ET) from selected plants. The standard width for ETS beds is 1.5 metres ranging up to a maximum of 3.0 metre and 0.45 metre depth. Plants in the ETS beds absorb effluent into their root systems and then release water to the atmosphere through their leaves. This process is called transpiration. Plants commonly used for this purpose include flax, toitoi (not Pampas grass), taupata (Coprosma repens), kiekie (Freycinetia banksii), panakenake (Pratia angulata), and many more. 

For more information, please refer to A Guide for Planting and Restoring the nature of Waitakere City.

ii. Dosed Aerobic Soakage Beds (ASB dose loaded)
These are 1.2 metres wide and 0.35 metres depth and they are planted out like ETS beds but are shallower than standard ETS beds. The effluent is dosed into the disposal field, a large volume of effluent is released from the septic tank ensuring maximum spread of effluent over the disposal field. (Note: ABS and ETS beds are planted out in the same way)

Treatment Plants/Sand Compactors/Low Pressure Effluent Distribution (LPED)
These systems treat the effluent by aeration or filtration to a level that will allow compensated dripper-lines to be used as disposal fields. These fields are located either in the topsoil layers, where greater bacterial action occurs, within lawns and gardens, or in bush surrounded by bark and mulch. (These systems should not be used in vegetable gardens and should be fenced off where livestock or heavy vehicles have access).

Protect the disposal field

You can protect your disposal field by:

• Keeping vehicles, heavy animals (such as horses and cattle) and deep rooting trees off the field
• Keeping children off disposal fields, especially in winter
• Keeping a written record of the dates of installation, pump-outs and maintenance inspections, as a case history assists if problems should arise.

How problems occur

• The disposal field blocks when sludge or scum passes from the septic tank into it, or unsuitable materials are flushed into it e.g. rags, sanitary pads, plastics etc.;
• Vehicles park on or drive over the disposal field;
• The distribution box is not evenly loaded causing part of the disposal field to flood;
• There are no cut-off drains above the disposal field;
• There is no maintenance of cut-off drains, causing the disposal field to become water logged;
• Roof rain-water discharges into the septic tank;
• The roots of trees and bushes grow into the septic tank and pipes of the disposal field, causing cracks and blockages;
• The disposal field has been poorly sited e.g. near waterways or in boggy soils
• Rainwater enters the septic tank via broken lids, low and broken gully traps.

Maintenance

You can keep your wastewater system working efficiently by observing some simple rules.

• Maintain soakage field areas by mowing or trimming plants in evapo-transpiration beds. This ensures that the disposal field operates at maximum efficiency.
• Alternate disposal areas; if you have a distribution box, alternate flow between the disposal trenches over the summer months, allowing part of the field to rest.
• Don't flush chemicals such as bleach, oils, fats, chlorine, paints etc into your wastewater system.
• Use toilet cleaners recommended for septic tanks.

You have a responsibility to keep your wastewater system in good working order.  If you are having problems, please contact us.

Tell-tale warning signs

Wastewater systems generally give warning that they are about to break-down or fail completely.
Tell-tale signs that your system needs attention include:

• Effluent or wastewater on the ground around the septic tank and disposal field area
• Strong odour coming from the septic tanks or disposal field
• Slow running drains or toilets.

Risks

A failed septic tank is a serious health and environmental hazard and can lead to:

• Risk of infection to you, your family, pets and farm animals
• Pollution of streams, beaches, fish and shellfish beds
• Contamination of drinking water supplies
• Breeding of pests including flies, mosquitoes and rodents

Good Practices

• Avoid appliances that are heavy water users.
• Avoid flushing sanitary pads or tampons, paper tissues, paper towels, disposable nappies, cigarettes, rags, plastics or other materials into the wastewater system.
• Put car engine oil, cooking oil or grease into appropriate containers for disposal.
• Compost vegetable matter and cooking scraps.
• Avoid using waste disposal units (they overload your system with excess solids and water).
• Do full loads of washing.
• Ensure roof stormwater is diverted away from gully traps and the disposal field.
• Dispose of acids, pesticides, medicines, paint or thinners or other chemicals in approved containers.

Tips

To protect your wastewater system, the environment, yourself and your neighbours, remember the following tips.

Reduce sludge build up by:

• Scraping all food off your dishes and remove all fats before washing; and
• Keeping all possible solids out of your wastewater system.

Efficient water use
Remember less water in = less water out. Efficient water use increases the performances of your wastewater system.

• Use water efficiently by installing "AAAAA" rated appliances, such as 6/3 litre dual flush toilet, low water usage washing machines, water efficient shower heads and taps.
• Install a water saving device such as a 'gizmo' in the toilet cistern.

Pump-outs

• EcoWater pumps out your septic tank approximately once every three years. This helps to prevent solids from getting into the disposal fields causing them to block.
• Pump-outs are charged for as a rural sewage charge in your land rates.
• A letter will be sent to you in advance of when your septic tank is due to be pumped out and a notice will be left, including a report on any defects found.

If you have any enquiries regarding when your tank was pumped or is due to be pumped please contact us.

Alternative Systems

Introduction

This information has been designed to provide an overview of the types of on-site wastewater systems that are available in New Zealand, and to assist you to make an informed choice on the type of system that may be appropriate for your site.

A variety of wastewater disposal technologies are available in New Zealand with a lot of this technology having been used in countries like America, Sweden, and Australia.

Manufacturers have supplied information and Waitakere City supplies this information in good faith to enable people to be more informed regarding the choices that they make.  Wastewater disposal systems in Waitakere City are required to comply with the Building Act, Codes of Compliance, Council by-laws, and obtain ARC consents where required.

Any new buildings or building alterations resulting in additional effluent requires the wastewater disposal system to be designed by a Registered Engineer familiar with wastewater disposal, this includes reporting on, certify a system, and preparing a maintenance programme.

If an existing system is operating ineffectively then a drainlayer or Engineer familiar with septic tanks and wastewater technology should be consulted as to the best way to remedy the system.

To ensure that an existing system remains efficient, the home owner should ensure that they become familiar with the system, add water saving devices where appropriate, eliminate roof water from going into the system, and divert overland flow .

If the property is very small, or has other constraints i.e. stream through the property etc is commercial or uses more than 2000 litres per day then an ARC discharge consent is likely to be required in addition to Council consents.

Public Responsibilities

Every householder has a responsibility to ensure they are adequately treating their wastewater within the boundaries of their property.

All septic tanks and wastewater systems must operate without creating a nuisance or discharging into storm water systems, which generally end up in streams.

Planning Considerations

General

The type of wastewater system installed depends upon its projected level of use, the availability of access for installation and construction, and the operational and maintenance requirements. Technical service, back up, operation and maintenance skills may also influence technology choice.

Installing the appropriate system to suit site conditions and frequency of use is the challenge facing wastewater disposal in non-reticulated areas. Factors that must be considered when choosing a wastewater disposal system follow.

Type of Facility

• Residential, household, holiday home.
• Walking track and/or picnic areas.
• Community clubs, accommodation, and public facilities.

The type of facility and its location dictates the level of service and provision for user convenience. The system to be chosen should be linked with the use of the building and future usage.

Use and Demand

Before installation each facility should have its requirements assessed based on:

• Number of residents per household.
• Usage pattern on a daily, weekly, monthly and seasonal basis.
• Estimated wastewater outputs, both "blackwater" and "greywater".
• Future demand for extended and/or new facilities.

For example a characteristic usage pattern for baches is seasonal variation where the facility may be used extensively over a short period, and then left unused for a long time. Public facilities in coastal holiday areas are also characterised by high ratios between peak and annual average demand. Highly resilient wastewater services, which can respond to wide loading variations, are required in these cases, and in all cases engineering calculations must be based on maximum use even if this is only for three weeks or so per year. The result of designing a facility on a lower use capacity may be breakdown of the sewage treatment process resulting in foul odours and possible overflow of raw sewage. There is nothing worse to a property owner than this eventuality when there are a large number of people needing to use the toilet facilities.

Economic Factors

Decisions on systems should take into account the overall cost of the system over its life. Costs include capital costs for initial purchase, maintenance (such as septic tank pump-outs), and expected life until replacement or refurbishment.

Design Factors

The wastewater system will need to be designed by a registered Geotechnical Engineer so it will meet the requirements of the specific site. The usage level, supply options and environmental constraints will determine the design criteria in any situation.

Use Levels

As already indicated, use levels for households will need to be taken into account. This is not only important for selection of a type or method of wastewater system, but also plays a part in the engineering design specifications of the specific wastewater system.

Disposal system design must be based on the maximum expected use, and not the average use. Designing on average use is one of the main causes of failures of on-site disposal systems.

Services

Services, which will affect the choice of wastewater disposal system, are availability of water, provision of electricity, mechanised wastewater treatment, ventilation, etc.  Different wastewater disposal options require different services to be able to operate. Some require electricity, while others rely on a good supply of reticulated water, which may be unavailable in a bach relying on rainwater tanks.

Environmental Constraints

Environmental constraints relate to the environmental sensitivity of the locality in which the wastewater disposal system is to be sited. These constraints include soil conditions, depth to ground water, overland flow and proximity to streams and lagoons. The biggest constraint is the type of soil that a wastewater system will be installed in.  For example impermeable subsoil will not allow for soakage in a drainage field, and would be an inappropriate environment to install a traditional septic tank system.

Maintenance Plans and Agreements

A maintenance plan is required at the time the system is lodged for consent. This maintenance plan needs to be consistent with information in T.P.58 particularly Appendix C; Appendix D; Appendix F; Appendix H; and Appendix I.

The Registered Engineer lodging the consent for the system completes the Maintenance Plan. The maintenance agreement is normally with the manufacturer of the system as he has the most knowledge of the system.  A good maintenance agreement should have details of the supplier installer/drain layer/electrician with contact details.

It should contain details of the water supply, occupancy and use.  It should then look at the system and define frequency that maintenance or checks should be done for each component.

It should include avoiding use of undesirable substances, water conservation, enhancing evapotranspiration, discourage access to disposal areas, and include a regular walk over of disposal areas looking closely for any sign of failure.

Onsite Wastewater Disposal Technology

Technologies available for on-site wastewater disposal can be broadly categorised into variants as follows:

1. The Standard Septic Tank
2. Multi-chambered Septic Tanks
3. Aeration Treatment Plants
4. Sand Filters
5. Textile Bed Reactor
6. Compost Toilets
7. De Centralised systems (including Air Vacuum Plants)
8. Waterless Toilets

Standard Septic Tank

The standard septic tank unit is a simple "single chambered" solids settling device that stores, digests, and consolidates sludge and scum before eventual removal as "septage".  Build-up from household use creates overflow that is discharged to a subsurface soil soakage field system. Tanks are usually rectangular and constructed of concrete, and may either be precast or built in-situ. Construction and materials must be durable and water tight, the tank must be installed in a manner that enables ready access for pump-outs (desludging), and is protected against uplift due to rising groundwater levels.

Multi-chambered Septic Tanks

Multi-chambered septic tanks have been developed to increase the quality of effluent output. This is achieved by either providing a pathway through a series of chambers, or by employing digestive tanks and directing different effluent qualities (e.g. greywater from the bathroom, kitchen, and laundry) into separate chambers.

The "Ecotank" is an example of a septic tank containing three chambers. The first chamber is an empty vault where blackwater and greywater settle out solids. Chamber two has a coarse mesh that filters the effluent and provides surface area for microbial growth. Chamber three is an upflow rock filter that has surface area for microbial growth, this assists in the treatment of the effluent.  Each chamber has a specific function to enhance the treatment of effluent before it passes out into the soakage field.

A second style of multi-chambered septic systems is the use of digestive tanks. These provide wastewater servicing via separate treatment of blackwater (toilet flow) and greywater (sullage from kitchen, bathroom and laundry). The separate flows are directed to different compartments in a single tank system or to separate blackwater / greywater tanks (dual septic tanks). Twin plumbing is required with digestive tanks. The advantage of the digestive tank concept is the improved treatment due to separation of low-flow high-waste loads (i.e. toilet waste) and high-flow low-waste loads from the bath, kitchen and laundry.

Two septic tanks in series with a total combined capacity 2/3 greater than the conventional septic tank is the third method of multi-chambered septic tanks. This has been widely adopted throughout New Zealand. Hydraulic buffering within the first tank aids in reducing turbulent overflow of solids, when volumes of water from the washing machine or bath enter the tank, and assists in the settling of solids. The second tank allows further solids reduction and biological treatment to produce a high quality effluent output. The second stage tank is generally 30% smaller than the first tank.

Aeration Treatment Plants

Aeration treatment of effluent is an effective means to dramatically increase the biological activity within a septage.  Introducing oxygen into the tank enhances the aerobic activity of microbes thereby increasing the biological breakdown of suspended and dissolved effluent particles. This process dramatically improves the quality of effluent entering the soakage field.

Aeration treatment systems generally utilise other design features for wastewater treatment, such as multi-chambered configurations, and filters.

Final effluent treatment by chlorination is also available in most aeration treatment systems.

Sand Filters

Wastewater is gravity fed from the house into a septic tank with an effluent filter. The filtered effluent from the septic tank is then pumped evenly over a sand bed and the effluent is treated to an exceptionally high quality by biological activity as it passes through the sand bed. The treated effluent is collected at the bottom of the sand bed and gravity fed to a holding chamber. From here it is distributed by pump to a subsurface drip irrigation system. The sand bed is generally 3 meters square, although it can be engineered to suit the size of the site.

Textile Bed Reactor

A textile bed reactor has been developed which works like the sand-filter with effluent being sprayed on hanging layers of textile. The textile surface are can process a large amount of effluent, therefore requiring less land area for the whole system than would be required for a sand filter system.

Composting Toilets

Composting toilets are where human waste (blackwater) is collected, stored, and consolidated via natural or controlled dehydration and dewatering processes. Bursts of air introduced after each use dehydrates waste material and ensures biological activity is maintained at a steady rate. The composted material moves steadily down a slope and builds up within the vault at the exit door where it can be disposed off. On average composted waste material requires disposal once a year.  This material is disposed of by digging it into the ground.

Composting toilets have two principle designs: solid-fluid waste separation, where the fluid is treated in a separate disposal field, and solid-fluid waste together.

Decentralised Systems

Suitable for small and mid sized communities, neighbourhood clusters, commercial properties, sensitive areas, and sewer expansions.  A cluster of houses or properties shares a single treatment plant and disposal field that is on common ground. There are a number of treatment options but normally a re-circulating textile bed reactor is the preferred option.

The lines to the treatment plant are sealed with no manholes of other breaks, because of this the system has no solids or infiltration, and treatment plants can be 90% smaller then other conventional plants.

Air Vacuum Plants as part of Decentralised Systems

Air Vacuum Plants are not widely used in New Zealand but are used quite extensively in America and to some extent in Australia. They are often used in decentralised systems.

Vacuum Toilets offer optimum flexibility in sanitary liquid waste collection and transport through the use of a Vacuum Drainage System. This system, utilizing vacuum toilets, can be installed in buildings located where there is a need to control and conserve the amount of wastewater produced in each flushing cycle. The use of this technology will help solve the problems of water conservation and sewage disposal.

Reasons for selecting vacuum toilets:

• Limited water supply
• Expensive water and sewer hook up fees
• Reduction and control of water consumption
• Eliminate the common problems of gravity drainage systems; wastewater can be lifted vertically up to six meters from point of collection.

Waterless Toilets

Waterless toilets offer a good solution for sites that have difficulties installing a disposal field.

The waterless toilet works on the same principal as a composting toilet, with solids being collected and composted in a natural process, and no flushing system. Differ slightly from composting toilets as they generally have some electrical components; this can be options such as a fan to vent any odours, or a heating element that evaporates urine and liquids so aiding the compost process.

Ancillary Items

To enhance performance of on-site wastewater treatment, other items can be added to the system as listed below:

• Dosing Siphons (Low Pressure Effluent Distribution)

One of the problems with a traditional drainage field is that the end closest to the septic tank takes most of the load and can get blocked and overloaded. This is because the field is constantly being fed by a slow trickle of effluent, which never reaches the extremities of the system.

With a dosing siphon the wastewater from the house is collected in a normal septic tank.  Effluent is filtered to remove most of the suspended solids to protect the siphon and the trenches. When the volume reaches a predetermined level the siphon automatically discharges into the drainage field. With only 2-4 doses a day the trenches have plenty of time to soak away and recuperate.

Biological Treatment

These products are biodegradable bacteria and enzymes that break down grease and the solid matter. They improve the efficiency of the septic tank system. However, once a nuisance condition arises it is not likely that biological treatment solutions will remedy the situation and they should be regarded as a preventative measure for grease traps and septic tanks.

Water Reduction

The less water that goes into a wastewater treatment system, the less loading there will be on the system. Reducing water can be done by reusing or recycling the grey water, and by reducing the original amount of use.

Water saving devices can easily save a third or more of water that is used in a home. This has the dual benefit of reducing the load on the wastewater treatment system, and reducing the demand for water. Examples of water saving devices are low flow shower heads, water saving toilets cisterns, and water conserving household appliances.

Greywater Recycling

Grey water recycling systems take the greywater from the bathroom, and or laundry and treat it for reuse in flushing toilets or outside irrigation.  With some de-centralised systems the whole effluent can be treated, disinfected and returned to the house for use in toilet flushing and outside tap use.

Ultra Violet Disinfection

Ultra Violet Disinfection can be used to sterilise outflow to ensure that it is clear of any microbial activity.

Effluent Filters

Filtering effluent before output can be achieved in either a single or multi-chambered tank. Filters increase the quality of effluent by restricting the exit of very small-suspended particles into the soakage field. This allows full biological breakdown to occur in the tank, and reduction in clogging of the dispersion field.

Filters require cleaning to remove large build-ups but some slime needs to remain as this is biofilm which aids the filter process.

Adding a filter to an existing tank is also possible and will help to increase its efficiency.

Rainwater Catching Devices

Rainwater catching devises can be used to supply water for your toilet so saving on water use from the local supply network. View information on rainwater tanks.

Preventing wastewater overflows

Wastewater overflows are a risk to you, your neighbours and the environment. We need your help to stop the problem!

Fat and grease from cooking are two of the biggest culprits in blocked drains. They can be tipped down the drain when they're warm but they don't travel very far before they cool and solidify, blocking the pipe.
Don't pour your cooking oil, fat or grease down the drain, instead:

• Put it into the compost bin or collect cooled oil in a covered container or plastic bag and put it into the bin.
• Before you wash plates or pots and pans either wipe them with a paper towel or scrape them into the rubbish.

Other ways you can help:

• Put all rubbish where it belongs â€" in the bin! It might seem easy to flush nappies, condoms, tampons, sanitary pads and cotton buds down the toilet, but they increase your risk of a blocked pipe.
• Plant trees and shrubs carefully.  Tree roots are a major cause of blocked pipes and can damage buildings, pavements, fences as well as pipes. So take care in selecting your trees and deciding where to plant them.
• Maintain your drains. All the drains and pipes on your property are your responsibility. It is important to keep them in good working order
• Food scraps, including tea leaves and coffee grounds, also help block drains. Please put them in the compost or the rubbish. Installing a standard sink strainer will also help.
• Save water. The less water you use the less wastewater you create and the less you pay on your water bill.
  
  Help us to help you! Blockages are an ongoing problem - preventing them is everyone's responsibility.

My sewer is blocked/overflowing/faulty who do I contact?
Before you call a plumber, contact us first. We will check where the problem is, as it may be a blockage in the public pipes which are the Council's responsibility to fix.  If the fault is in your private wastewater pipes then the cost to repair it is the owners responsibility.

Please note: Council will not reimburse for any private drainage work associated with public pipes.