Ryedale District Council


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Septic tanks and cesspits

Information and advice on septic tanks and cess pits.

Due to the unavailability of a suitable disposal point in Ryedale we are unable to provide a septic tank emptying service, however there are private companies operating in the area who will be able to assist.


A septic tank is a type of biological sewage treatment system. Naturally occurring bacteria break down the solid matter, reducing its volume. The liquid element is discharged to a soil treatment system. The accumulated solids in the septic tank need to be pumped out periodically (generally once a year).

Septic tanks may be constructed in brick or blocks, although modern types are pre-formed in reinforced fibreglass.


Ideally septic tanks should not be sited close to houses. Please visit the North Yorkshire Building Control Partnership for more specific advice. Not all sites are suitable for septic tank systems. The main concern is the type and porosity of the soil at the site. Also the depth of the water table can be a problem if it reaches too high a level in the wet season. Generally septic tank systems cannot be placed in areas where the depth to bedrock or the water table is less than 90cm.


Percolation tests need to be carried out to ensure that there is sufficient land to take the effluent away from a septic tank. The tests should be carried out in accordance with BS6297 : 1983 to determine the size of the effluent drains or soakaways, which must be sited at least 6 metres from a water course. It may not always be possible to install soakaways; soil conditions or other factors such as ground water levels may make them inappropriate. In this case you will need to consider some other form of drainage. Before constructing soakaways it is a requirement to obtain "Consent to Discharge" from the Environment Agency. The Building Control Partnership will also advise you on how to perform the percolation test.


A cesspool or cesspit is a sealed underground storage tank that retains the sewage until the time of disposal. It may be brick or block construction or manufactured in steel or reinforced glass fibre and should have a minimum capacity of 18,000 litres.

Where can a cesspool be sited?

A cesspool should be sited so that there is no risk of polluting water supplies and as far as practically possible from any inhabited building.

Can a cesspool go wrong?

The tank can overflow or may leak which is an offence under the 1936 Public Health Act. In addition if it pollutes a watercourse the Environment Agency may take legal proceedings under the Water Resources Act 1931. This can lead up to a fine of £20,000 and 3 months imprisonment.

If it leaks a drainage engineer should be called out to remove the waste and clear up the sewage. The cause of the leak should be identified and remedied.


Cesspools: check the level in the tank regularly, do not let it overfill. Have it emptied at regular intervals: these will become more frequent if you install a dishwasher for instance.

Septic tanks: do not use excessive amounts of household detergents or bleaches; these upset the biological balance of the system. Do not overload the system by connecting rain or water drains to septic tanks or cesspools.



  • have your septic tank system professionally fitted, following local guidelines and regulations
  • put all your wastewater from your home into the system
  • know where your septic tank and drainage field are located
  • have your system inspected regularly
  • desludge the tank when necessary
  • act immediately if you find a blockage or any sign of a problem
  • if necessary, seek professional help (see "Drain and pipe cleaning, Plumbers merchants or Sewage consultants" in the telephone directory)
  • keep note of any maintenance work
  • ensure all manhole covers are accessible
  • ensure that any air vents are not blocked
  • keep the drainage field protected
  • divert sources of clean water, like roof drains, away from septic tank systems
  • wash dishes in a dishwasher whenever possible (fat is converted into soap in a dishwasher)
  • use toilet fresheners, mild detergents, fabric conditioners and washing powders and liquids in moderation without upsetting the natural balance of the septic tank. All active ingredients in soap and detergents should be biodegradable by law and should be safe for septic tanks in normal use
  • use bleaches and disinfectants sparingly – as they can kill the friendly bacteria which make the septic tank work.


  • fats, oils or heavy grease should not be poured down the drain;
  • paints, solvents and motor oils should not be put down the drain;
  • never dispose of garden chemicals and pesticides into the septic tank;
  • don't use the toilet or kitchen sink as a rubbish bin;
  • don't empty chemical toilets into drains or septic tanks;
  • nappies, sanitary items, plastic or similar items should not be disposed of into the system – "bag it and bin it" instead;
  • don't dig or drive over the drainage field, or cover it with a hard surface;
  • don't block air vents;
  • don't desludge your tank too often;
  • don't allow effluent to collect on the surface of the ground; and
  • don't enter a septic tank – dangerous gases are produced by the natural treatment process.

Problems occur only very rarely, but should be remedied as quickly as possible.


Advice on investigating complaints of nuisance from drainage systems, leaking tanks or defective soakaways that require the owner or owners to remedy the problem can be obtained by submitting an Enquiry Form. Failure to remedy the problem can result in legal action against the person responsible under the Public Health or Building Acts.



Contact us

Ryedale District Council
Ryedale House
Old Malton Road
Malton, North Yorkshire
YO17 7HH

Email: Contact the Council

Phone: 01653 600666

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