New septic tank rules

New septic tank rules came into force on 1st January 2015. Regardless of age, the drainage system must meet The Environmental Agency General Binding Rules.  Two of the relevant British Standards currently in force are;

BS EN 12566 – 3:2016 Small wastewater treatment systems for up to 50 persons. Packaged and/or site assembled domestic wastewater treatment plants and BS 6297:2007 for drainage fields

Installations installed prior to 1983 are not required to meet these standards however, the system must not breach the 2015 General Binding Rules.

If you are considering, buying or selling a property, it is the vendor’s responsibility to detail to the purchaser in writing that a sewerage discharge system is in place and must include a description of the treatment plant and drainage system. From 1st January 2020 owners/operators are liable to unlimited fines if the drainage system does not meet these rules. If you are buying a property it is imperative to check, prior to purchase that the system is compliant as the cost of upgrading the system may be negotiated in the sale price.

There are several options available to septic tank owners/operators and these vary depending on how the effluent is discharged from the septic tank.

If the effluent discharges directly into a watercourse, a treatment plant (aerobic/anaerobic digestion) will be required, if connection to mains is not possible. Typically, aerobic systems are used, connected to an electrical supply to agitate the effluent breaking it down into a 95% clean liquid that is permissible to discharge into a water course.

If the effluent discharges into the ground, a drainage field or drainage mound may be installed. This comprises of laying perforated pipe in a ring main loop after the septic tank or treatment plant. The size of the drainage field will be dependent on the number of persons the system serves or volume of water discharged daily and the rate at which water naturally drains through the soil. To determine this, two tests are required;

  • Water table test
  • Percolation test

These tests involve digging a test pit in the proposed location of the field drainage system and monitoring natural water flow rates for specific volumes of water over a timed period.

If the water table test shows that a drainage field is not suitable a drainage mound may be installed, this also incorporates a ring main loop of perforated pipes but are laid in a mixture of sand, gravel and soil above the existing ground level.

Whether you are looking to install a new drainage system or would like to check whether your system is compliant, Cockrams uses specialist equipment to carry out a variety of services, including: percolation and water table tests, location and size of existing systems and whether or not they meet current British Standards, measured/topographical surveys, specification and tendering, project management, ensuring the property system meets the General Binding Rules.