Guide
The septic tank rules, explained for Suffolk homeowners
If your home is off mains drainage, the Environment Agency's general binding rules decide what your system must do. Here is what they mean in practice.
The short version
If you meet the rules that apply to your system, you do not need a permit. The rule that catches most Suffolk properties is simple: a septic tank must not discharge directly to a watercourse, such as a ditch, stream or river.
If your septic tank discharges to a watercourse
The official guidance says to put it right as soon as possible, using one of these options:
- Connect to a mains sewer, where one is available.
- Install a drainage field so the tank discharges to the ground instead.
- Replace the septic tank with a small sewage treatment plant.
Conversion units fitted inside an existing tank only count if they were installed before 2007. A reedbed or other secondary treatment after a septic tank must meet the relevant British Standard to discharge to a watercourse.
When you buy or sell
A property with a septic tank discharging to a watercourse must be dealt with as part of the sale. Buyer and seller agree who does the work, and the seller must give the buyer written details of the system. See our guide to selling.
Ongoing duties for every system
- Have the tank or plant emptied regularly by a registered waste carrier.
- Keep it maintained and repair faults such as cracked walls or pipes.
- Keep records of emptying and maintenance.
- Stay within the volume limits for small discharges.
This is a summary, not legal advice. The official guidance is published by the Environment Agency on GOV.UK under "General binding rules: small sewage discharge to a surface water" and the matching guidance for discharges to the ground.
Rules questions
What are the general binding rules?
They are the Environment Agency's conditions for small sewage discharges in England. If your septic tank or treatment plant meets the rules that apply to it, you do not need an environmental permit.
Can a septic tank discharge to a ditch?
No. A septic tank must not discharge directly to a watercourse. The outflow must go to a drainage field, or the tank must be replaced with a treatment plant that meets the British Standard.
Do the rules apply in Wales or Scotland?
No. The general binding rules described here apply in England. Wales and Scotland have their own regulators and requirements.