New septic tank regulations explained

Septic tanks that discharge sewage into ditches or surface water must be urgently replaced or upgraded, according to Environment Agency rules announced last October. Here, we look at the rules and explain what they mean for homeowners and businesses using a septic tank.

What are the new septic tank regulations?

The new regulations state it’s an offence to discharge wastewater into watercourses or the ground without an environmental permit or exemption. So, all septic tanks that release sewage into surface water must be upgraded or replaced to a sewage treatment plant, or the discharge must be redirected to a dedicated drainage field. The government set a deadline of 1 January 2020 for septic tank owners to either secure permits or exemptions, divert the sewage into a drainage field or upgrade septic tanks. Since 2015, the Environment Agency has banned all new septic tanks from discharging into surface waters.

How can I make sure I’m compliant?

If your septic tank releases sewage into a waterway, you must upgrade or replace it as soon as possible (the deadline was 1 January 2020).

Or, you may be able to:

  • Apply for a permit to continue to release sewage into the water (only in exceptional situations)
  • Fit a drainage field so the wastewater can be released safely into the ground
  • Upgrade or replace your septic tank with a sewage treatment plant, which treats the water and can discharge safely into a ditch or watercourse.

What are the general binding rules set by the Environment Agency?

Once your septic tank has been upgraded or replaced by a sewage treatment plant, or you’ve received a permit or exemption, it can discharge into surface water.

Then, you must follow these “general binding rules” set out by the government:

  • Wastewater must be domestic only – i.e. come from a toilet, bathroom, shower or kitchen of a house, flat or business (e.g. hotel, pub or office)
  • Sewage must not cause pollution
  • If you’re releasing sewage to the ground, you must use a drainage field or apply for a permit to discharge to a well, a borehole or a groundwater source protection zone
  • If you’re discharging to the ground, you must apply for a permit if you release more than 2,000 litres a day
  • Commercial properties like hotels, restaurants, offices and holiday homes must follow British Water’s flows and loads guidance

All septic tanks and sewage treatment plants fitted after 1 January 2015 must follow these rules:

  • Septic tanks for individual domestic properties cannot be within 30 metres of a mains sewer
  • For septic tanks serving multiple domestic properties, multiply the 30-metre minimum distance by the number of homes, e.g. two dwellings – 30 x 2 = 60 metres from a mains sewer
  • You must only release sewage treatment plant discharge into waterways with a year-round flow
  • Your chosen watercourse cannot be in a designated sensitive area

Applying for permits, exemptions and building regulations approval for sewage systems

If you are releasing to a body of water, it’s now essential to use a sewage treatment plant, rather than a septic tank. Users with a discharge of more than 5,000 litres a day must apply for a permit. Visit to apply for a permit or for more information about the Environment Agency septic tank regulations.

All new sewage treatment systems require building regulations approval and may require planning permission, too. You might be able to apply for retrospective building regulations approval if you failed to secure this before installing your wastewater treatment plant – check with your local council for more details.

What’s the best option for septic tanks without a drainage field?

The safest and most environmentally-friendly option for septic tanks that currently discharge wastewater into a watercourse is to upgrade the tank to a sewage treatment plant or replace it with a new sewage treatment plant.

Upgrading or replacing your septic tank with a wastewater treatment plant will have the following benefits:

  • Save money – sewage treatment plants are cost-effective to run.
  • Low maintenance – sewage treatment plants require very little maintenance and are a hands-off way to manage your off-mains water
  • Environmentally-friendly – wastewater treatment plants treat sewage, releasing purified effluent safely into watercourses without any harmful effects on plants and animals
  • Fully compliant – upgrading or replacing your septic tank with a sewage treatment plant gives you the peace of mind your wastewater system is fully compliant with Environment Agency guidelines.

To speak to us about upgrading or replacing your septic tank to a sewage treatment plant, give us a call on 01706 813733 or email [email protected], and an experienced member of our team will be happy to discuss your options.