Gardening products as well as beer and dairy are some of the things you should never pour down the drain if you’ve an on-site wastewater treatment system.

In this article we cover:

  • Typical maintenance schedule
  • What it should include
  • What not to put down the drains
  • Types of cleaning products to use
  • Watchpoints and warning signs

Any sewage system requires regular maintenance, so find
out what yours requires and implement a programme
which includes checking and servicing it.

Responsible ownership is as much about not wanting to pollute as a legal requirement. The installers will generally give you a price for this work.

A typical programme might include an initial six-month service, followed by another six months later and annual services thereafter. Do keep a record of all maintenance work.

The schedule could cover:

  • De-sludging (although note that Northern Ireland ratepayers not connected to mains sewer are entitled to one free desludge per year).
  • Sampling and testing the quality of effluent being discharged.
  • Checking bacteria health.
  • Checking the functioning of the aeration system.
  • Checking and replacing, if necessary, the mechanical components.
  • Testing the alarm system if fitted.

Your household will play a very important part in keeping maintenance costs down, by ensuring that nothing enters the system that might damage it or cause it to malfunction.

Avoid fitting a waste disposal unit as PWWTPs are designed primarily to process liquid waste, so too much solid waste can overwhelm the treatment system and can also contribute to methane production (considered one of the worst greenhouse gases).

You should use biodegradable or low phosphate washing and cleaning products, only use as much as you need and spread washing and cleaning activities evenly throughout the week.

With any system, a key process is the biological breakdown stage, where the naturally occurring bacteria need a friendly environment to survive and do their work. That environment is entirely created by whatever you put down the drains, so too many harsh chemicals can harm or kill the friendly bacteria, resulting in a system which will fail to work properly and which will take a long time to recover.

An online search for something like “eco-friendly products for domestic cleaning” will give you any number of alternatives to the usual chemical products. Your family and guests, including children and visitors should also be made aware of what not to put down your sinks, drains or toilets.

Contact with sewage can cause Leptospirosis and septic tank gases can be lethal, so Protect yourself and your family by ensuring that all covers and lids or other access points to the sewage system are kept secure and in good condition.

If in doubt about a possible malfunction, stop using water immediately and get professional help for any repair or maintenance work.

Things to watch out for include:

Prevent hot tubs, swimming pools or surface water from entering and overloading the sewage system.

  • The area over a sub-surface irrigation system should not be compacted by vehicles or other equipment and should not be used as a storage area for stockpiling construction or gardening materials.
  • Tree roots can invade and damage pipes and tanks, so avoid planting trees too close to a PWWTP or a sub-surface irrigation area.
  • Routinely check for signs of a malfunctioning system. Sewage backing up may be identified by gurgling pipes or gully traps, slow-draining fixtures and strong odours around manholes or the tank area. Any of these will require immediate attention.
  • Pooling water, especially discoloured water, or unusually abundant grass over the sub-surface irrigation area may indicate a system failure. Any signs of pollution in nearby ponds or watercourses will require urgent action.