You have moved into a house with a septic tank or small sewage treatment plant, what are my responsibilities?

The details below are taken from the Environment Agency’s website:

As the ‘operator’ of a septic tank or small sewage treatment plant you must check you meet the general binding rules. You must apply for a permit if you do not.

You’re an operator if any of the following is true:

  • you own the property that uses the system;
  • you own a property that shares the system with other properties - each property owner is an operator, and you are jointly responsible for complying with the general binding rules;
  • you have a written agreement with the property owner that says you’re responsible for the system’s maintenance, for example you’re renting and it’s in your tenancy agreement.

Contact the Environment Agency if you’re not sure whether you’re an operator.

What is a Septic Tank?

Septic tanks are usually a two or three chamber tank. Older tanks are usually brick or concrete, with newer ones more likely to be fibre glass or reinforced plastic.

When working correctly a tank will collect the wastewater, separate out the solids and discharge the effluent into the soakaway. If your septic tank is maintained and checked regularly by Roe Environmental Ltd these tanks provide many years of use.

How does it work?

Any sewage treatment system is just a way of slowing up the sewage to allow sufficient time for enzymes to naturally break up the contamination. The septic tank or treatment plant collects the sewage and allows the bacteria to break it down so the effluent is safe to soak away into the ground, or even enter a water course in some circumstances.

What is the difference between a Wastewater Treatment Plant (WWTP) and a septic tank?

Treatment plants usually have access to a supply of electricity which drives a small pump to aerate the wastewater.

Septic tanks have no moving parts, nor do they need a power supply, so they are cheaper to buy, install and run, but the final effluent will not be as clean. The effluent from a septic tank will always require further treatment in a soakaway.

Some small treatment plants are referred to as Package Treatment Plants. This is because they arrive at your house on the back of the lorry ready to be installed.

Why do you need to empty a septic tank?

During the treatment process you get a build-up of sludge at the bottom of the tank which needs to be taken out. A contractor such as Roe Environmental Ltd will remove this, and if possible will put the watery effluent back in, which is good because that effluent contains billions of the good microbes necessary for your tank to work.

Desludging is required once a year, but can be required more often.

There’s a scum on the surface in the tank. Is this OK?

Yes, as long as it has not gone hard. If the Fat, Oils and Grease (FOG) has hardened it will stop the air reaching the aerobic bacteria and stop the good enzymes being produced. The microbes in the tank would then die, and stop working properly. You should get Roe Environmental Ltd to de-sludge your tank when this starts to happen.

How often should I empty or de-sludge my tank?

You should de-sludge your tank in accordance with the manufacturer's recommendations, but yearly would really be the minimum amount we would recommend.

We’re thinking of installing a new tank. What should we do?

The Environment Agency’s website is very useful for this, but also please contact Roe Environmental Ltd for further advice.

What shouldn’t I flush down the toilet or pour down the sink with a treatment plant or septic tank?

Biocides, such as bleach or disinfectants are bad. Paints, engine oils, solvents or caustics. Physical products such as wipes, nappies and sanitary products will not break down, so will cause blockages or issues in the future, and can cause higher costs when you have a de-sludge.

Can I just put a dead rabbit in my septic tank to get it started?

This is the wrong sort of bacteria. The bacteria which your tank needs exist in nature in the soil, So, no. 

My tank stinks! What’s wrong?

Most likely that the microbes have died. You must add some bacteria to the septic tank immediately or empty the tank and start again. You then must think what has killed the bacteria off, as It’s highly likely to be a cleaning product you use.

What are my legal obligations if I live in a property with a septic tank or Treatment plant?

You have a legal responsibility to check the area where you release sewage once a month for signs of pollution. We can also provide a monthly service to do this for you at a very competitive rate.

If you release sewage into the ground, you must check for:

  • sewage smells
  • signs that your sewage isn’t draining properly (e.g. pools of water in the area where you release sewage)

If you release sewage into water, check for:

  • sewage smells
  • overflowing sludge
  • signs of white scum or foam on the water around the area where you release sewage

Keep good records of your servicing and maintenance that you have done on your system, also making a note of any problems you have had for future reference.

You could face a serious fine from the Environment Agency if you do not adhere to this.

How much does it cost to register my Septic Tank with the EA?


How do I register?

You can do it by post, but it’s very straightforward to register online on the Environment Agency website.

We have a reed bed. Will your products block this up?

No. They can only help.

My local farmer has offered to de-sludge my tank. Is this OK?

By law, de-sludging should be carried out by an operator registered for the carriage of such waste by the Environment Agency. It’s unlikely that your friendly farmer is registered, but Roe Environmental Ltd are.