Helpful Hints for looking after on-site sewage systems


Money spent on a good system is money down the drain if you don't look after it.

Keep the bacteria in the tank alive
Bacteria break down most of the solid material in the sewage and turn it into sludge. Without them, solid material would quickly fill the tank. The "good" bacteria can be killed by household cleaners, strong detergents, and toxic chemicals.

Reduce the liquid load into the tank
Wastewater from the washing machine and bathroom make up most of the load into the tank. Reducing this load helps the final treatment in the soil because the soil under the soakage treatment area doesn't get so wet. This is good because drier soils give better treatment.
As well as this, small loads take up less space in the tank, so they don't pass through so quickly. This gives the solids in the sewage more time to settle to the bottom, rather than escaping out of the tank and blocking up the soakage treatment area.

Reduce the solid load to the tank
Most solid material in the sewage settles on the bottom of the tank where it's broken down by bacteria. The end product is a liquid sludge at the bottom of the tank. Some things don't break down. They'll stay in the tank until you get it emptied.

It's your choice
You can be relaxed about what goes in and get the sludge removed every year, or you can reduce the sludge build up and get it removed every two or three years.

Protect your soakage treatment area
The soakage treatment area is where the treated sewage goes when it leaves the tank. It is the key to the safe disposal of effluent. Effluent from the tank still contains lots of germs. These germs don't disappear when the effluent soaks out of sight.

Germs survive best in wet conditions, so don't give them wet conditions! Keep the soakage treatment area as dry as possible by distributing the effluent at a low rate throughout the entire area. Don't let it all discharge beside the tank because this can create a permanently wet area where the germs will thrive.

Marking where the pipes have been laid is helpful when you want to plant trees, or change the system or find damaged pipes later. Having mushroom vents at the ends of the distribution lines is a good way of doing this, and gives you a way to check if the effluent is building up anywhere.


On-site Sewage - Your Legal Responsibilities.

After you've flushed the toilet or pulled the plug in the kitchen sink, where does your sewage and wastewater go? If you're in the country, it probably drains away somewhere in your backyard.

You might have a septic tank with a soakage treatment area, you might have a mini treatment plant, or you might just have a "long drop". Whatever you've got, you need to be sure it's legal.

What kind of permission do you need for your system?

A septic tank or mini treatment plant is a 'structure' that has a 'discharge'. Structures must have a building permit.

Regional Rules
Sewage doesn't stay in the tank forever. The treated part of it discharges to the environment.
If your sewage system discharges to land, or if you have a long drop, the discharge must comply with certain rules.

Discharge Permits
Every discharge of sewage to water in the Manawatu-Wanganui Region requires a discharge permit. It doesn't matter if the water is in a river, lake, roadside drain or under the ground. Discharges of sewage into soakholes, without treatment in an application area, go straight to groundwater and require a discharge permit.

Most importantly, don't let sewage leak into a river or any other body of water.

If you have any questions or queries, we'll be glad to help. Just get in contact!