Not on mains drainage? Key rules you need to know.

If you’re planning to install a new septic tank, sewage treatment plant or cesspool you need to comply with the latest regulations.

You can check the differences between a septic tank and cesspool here.

You will need planning permission and building regulations approval for any new installation. If your system was installed after 1 January 2015 you will need to apply for these permissions retrospectively. This isn’t necessary if your system was installed before 1 January 2015.

You’re responsible for your sewage treatment system if you own a property that uses its own system, or shares a system with other properties. If you rent your home, your tenancy agreement will state whether you’re responsible for maintenance of your sewage treatment system. If you’re unsure whether the system is your responsibility you should contact the Environment Agency.

Cesspools must be maintained and emptied regularly. You must ensure that it doesn’t leak or overflow. The Environment Agency or your local council can make you repair or replace your cesspool if it’s in poor condition.

The following general binding rules are for septic tanks and small sewage treatment plants in England (there are different rules in Northern Ireland, Scotland and Wales):

  • Sewage must be domestic in nature (i.e from a toilet, bathroom, shower and/or kitchen of house, flat or business);
  • Sewage must not cause pollution.

You may need to apply for a permit under certain circumstances whether the sewage from your system discharges into the ground (for example your garden or land) or into surface water (for example a river or stream).

Whether your property is residential, commercial (such as a hotel, restaurant or office) or holiday accommodation (for example a cottage or chalet) you can calculate how much sewage you discharge per day. Use the calculators here.

The following rules apply to all existing systems (that were in use before 31 December 2014), whether they discharge to the ground or surface water. You must ensure that:

  • You use the correct treatment system;
  • Your treatment system meets the right standards;
  • Your system is installed correctly and has enough capacity;
  • Your system is regularly emptied and maintained;
  • If you sell, you give the new owner details of the sewage treatment system in writing;
  • If you stop using the system, it is properly decommissioned.

If your system discharges to ground you must also check whether you’re in a groundwater protection zone 1 (SPZ1).

If your system discharges to the ground and was installed or came into use on or after 1 January 2015 (a “new” discharge), you must also:

  • Check if there is a public sewer nearby;
  • Ensure you have planning permission and comply with building regulations;
  • Check if your discharge point is near a designated sensitive area.

Read the rules for sewage discharge to ground in full.

If your system discharges to surface water you must also:

  • Make sure the surface water has flow;
  • If you’re using a partial drainage field, check that it meets the requirements.

Read the rules for sewage discharge to surface water in full.

Read more information on private sewage treatment rules and regulations on the government website.

For expert advice on the installation, maintenance, servicing and emptying of all kinds of septic tanks, cesspools and sewage treatment plants email us on or call 01634 250326. Free site surveys are available on request.

Why choose MTS?

  • 24/7 Reliability 01634 250326

    There is always someone to take your call - Our field service teams operate round the clock every day of the year.
  • Rapid response

    With hub depots throughout the region, we operate a highly flexible scheduling system. We instruct our nearest available tracked field service for the quickest response.
  • Competent first time fix

    Our fully qualified and experienced teams use high performance equipment to fix problems first time with no need for back up resources or second visits. We ensure the optimum solution for your needs.
  • Extensive range of waste solutions

    Our waste management services are available for both individual jobs and more complex packaged solutions. We offer a one-stop shop whatever your requirements and we are continuing to expand our range of services through innovation and investment.
  • Experienced and qualified team

    All management and staff receive full training and are qualified to demanding industry standards in their specialised disciplines. MTS invests in its people and, with low staff turnover, retains a considerable depth of experience to ensure Customers receive the best service. Email our team today at
  • Full QUENSH management systems

    MTS operates an integrated management system comprising the individual accreditations for ISO 9001 (Quality), 14001 (Environment) and 18001 (Health and Safety). Certified and regularly audited for compliance by BSI Customers are assured of rigorous processes and procedures supporting front line service delivery
  • Trusted service provider

    MTS is entrusted by major water companies across Southern and South East England to work safely to the highest performance standards under stringent environmental and financial control. Rail, airport and highway agencies similarly demand safe and secure services from MTS for the maintenance of critical infrastructure with minimum risk to the travelling public


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