The EA has maintained the permit requirements but has waived any obligation to register for an exemption, provided that the relevant criteria are satisfied.
Broadly, the septic tank (or sewage treatment plant) must be installed according to the manufacturer’s specifications and be large enough to handle the amount of sewage expected to be produced.
It must meet the British Standard for septic tanks and sewage treatment plants in place at the time it was installed (currently BS EN 12566) and it must be repaired or replaced if it isn’t in good working order. The system must be emptied at least annually whether or not it is full and also whenever it becomes full, if that occurs more frequently, by a company that is a registered waste carrier for the sludge to be removed.
If the septic tank or treatment plant is releasing sewage into the ground then a drainage field (infiltration system) meeting the British Standard in place at the time of installation (currently BS 6297:2007) must be installed. If it is in a tidal area, then the top of the pipe that releases the sewage must be below the “low water mark”.
A permit is still required if the sewage released isn’t domestic; sewage is domestic if it’s from a toilet, bathroom, shower, or kitchen of a house, flat, or businesses including pubs, hotels and offices. A permit must be sought where more than 2,000 litres of sewage per day is released into the ground or 5,000 litres per day directly into water. Similarly if you are in a groundwater source “protection zone 1” or within 50 metres of a well, spring, or borehole used to supply drinking water or water for food production then you will need to apply for a permit. This may make it necessary to ask neighbours if they take drinking water from a well, spring or borehole.