Legislation
A.1 Local authorities have powers to ensure that wastewater treatment systems or cesspools are adequately maintained.
Power to examine and test
A.2 Under Section 48 (Power of local authority to examine and test drains etc. believed to be defective) of the Public Health Act 1936, the local authority may test any cesspool, septic tank or settlement tank where it appears to them that they have reasonable grounds for believing that it is in such a condition as to be prejudicial to health or a nuisance.
Power in respect of overflowing or leaking cesspools, septic tanks, etc.
A.3 Under Section 50 (Overflowing and leaking cesspools) of the Public Health Act 1936, the local authority can take action against any person who has caused by their action, default or sufferance, a septic tank, settlement tank or cesspool to leak or overflow. They may require the person to carry out repairs or to periodically empty the tank.
A.4 This does not apply to the overflow of treated effluent or flow from a septic tank into a drainage field, provided the overflow is not prejudicial to health or a nuisance.
A.5 It should be noted that under this section action could be taken against a builder who had caused the problem, and not just against the owner.
Power to require repairs
A.6 Under Section 59 (Drainage of building) of the Building Act 1984, the local authority may require the owner or occupier of a building to carry out remedial works where a septic tank, settlement tank or cesspool is: a. insufficient;
a. in such a condition as to be prejudicial to health or a nuisance; or
b. so defective that groundwater leaks into it.
Disused septic tanks, cesspools, etc.
A.7 Also under Section 59 (Drainage of building) of the Building Act 1984, where a disused cesspool, septic tank or settlement tank is prejudicial to health or a nuisance, the local authority may require either the owner or the occupier to fill or remove the tank or otherwise render it innocuous.
Powers of the Environment Agency
A.8 The Environment Agency has powers under Section 85 (Offences of polluting controlled waters) of the Water Resources Act 1991 to prosecute anyone causing or knowingly permitting pollution of any stream, river, lake, etc. or any groundwater.
A.9 They also have powers under Section 161A (Notices requiring persons to carry out anti-pollution works and operations) of the Water Resources Act 1991 (as amended by the Environment Act 1995) to take action against any person causing or knowingly permitting a situation in which pollution of a stream, river, lake, etc. or groundwater is likely. They can require such a person to carry out works to prevent the pollution.
A.10 Paragraphs A.11 to A.22 give guidance on the appropriate maintenance of wastewater treatment systems and cesspools.
Septic tanks
A.11 Septic tanks should be inspected monthly to check they are working correctly. The effluent in the outlet from the tank should be free-flowing and clear. The flow in the inlet chamber should also be free-flowing.
A.12 If the flow is incorrect, the tank should be emptied by a licensed contractor. Some contractors offer annual maintenance contracts at reduced rates.
A.13 The septic tank should be emptied at least once a year. It is recommended that not all sludge is removed as it can act as an anaerobic seed.
A.14 If the tank is not adequately maintained and solids are carried into a drainage field/ mound, the sediments can block the pores in the soil, necessitating the early replacement of the drainage field/mound. Occasionally, it can render the site unsuitable for future use as drainage field/mound.
Drainage fields and mounds
A.15 The drainage field/mound should be checked on a monthly basis to ensure that it is not waterlogged and that the effluent is not backing up towards the septic tank.
Packaged treatment works
A.16 The outlet of the works should be inspected regularly. The effluent should be freeflowing and clear.
A.17 Maintenance will vary depending on the type of plant; regular maintenance and inspection should be carried out in accordance with the manufacturer’s instructions.
A.18 Where the treatment works serve more than one property, the developer may seek to get it adopted by the sewerage undertaker under Section 102 (Adoption of sewers and disposal works) or Section 104 (Agreements to adopt a sewer or disposal works at a future date) of the Water Industry Act 1991 (see Approved Document H1, Appendix H1-B).
Constructed wetlands/reed beds
A.19 Guidance on maintenance of reed beds can be found in BRE Good Building Guide No. 42.
Cesspools
A.20 Cesspools should be inspected fortnightly for overflow and emptied as required.
A.21 Typically they require emptying on a monthly basis by a licensed contractor.
A.22 Emptying frequencies may be estimated by assuming a filling rate of 150 litres per person per day. If the cesspool does not fill within the estimated period, the tank should be checked for leakage.
