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How do I know the septic tank I am inheriting is legally compliant and fit for purpose?


Purchasing a house with a private foul drainage system should not be daunting but as with all things unknown, fear can creep in about the state of the septic tank you are inheriting. Lets face it you will be able to see a couple of manholes and a vent pipe at best! You have heard about the new Environment Agency regulations that came into affect in January but how does this affect you and how do you ensure the septic tank you are inheriting is legally compliant and fit for purpose?

This is a prime example of when ‘Knowledge is Power’. The more information you can glean about the system from the Seller, the better. This detail will help inform and guide the WCI Engineer you employ to carry out a Home Buyer’s Drainage Survey at the property. The Home Buyers Drainage Survey will ensure that you will not be exposed to the daunting costs of rectifying or replacing an illegal system post competition. THese costs can be as high as £15,000!!


What information does the Seller legally have to provide to me?


Under the Environment Agency’s General Binding Rules, when you sell your property, you must tell the new operator (the owner or person responsible for the sewage treatment plant) in writing that a sewage discharge is in place. The information must include:

  • a description of the treatment plant and drainage system
  • the location of the main parts of the treatment plant, drainage system and discharge point
  • details of any changes made to the treatment plant and drainage system
  • details of how the treatment plant should be maintained, and the maintenance manual if you have one.
  • maintenance records if you have them

Before WCI visits a property to undertake a Home Buyers Foul Drainage Survey, a desk top study will be conducted. Key information will include location maps, sites designated for their wildlife interest (Site of Special Scientific Interest, Special Conservation Areas etc…), Source Protection Zones, Flood mapping, soil data and any Environment Agency permit information.


WCI would suggest asking the following questions


1. What private foul drainage system serves the property?

This could be a septic tank and drainage field, a reed bed, a sewage treatment plant, a private pumping station connected to the public foul sewer or a cesspool. Terms such as cesspit, soakaway, clinker bed or klargester may be used.

2. Is the system shared with other properties?

How many bedrooms does each property have?

3. Where is the system located?

Is it on land owned by you or a third party?, Is there an easement in place if the system is not on your land?, Do you have rights of access, and is a management company in place which sets out maintenance and emptying arrangements and payment of such activities? Do you have a plan of the system?

4. Where does the system discharge?

To ground via a drainage field or to a surface water i.e. ditch (dry, seasonally dry or flowing), stream, rhyne, stream, river. Ask for a sketch of the system including where it discharges.

5. When was the system installed?

Is there a Building Completion Certificate covering the installation of the septic tank? Do you have a Operations and Maintenance Manual?

6. How often has the system been emptied and maintained?

Has the seller kept receipts of each empty and service event or even an annual service report?

7. Does the system’s discharge have an Environment Agency Permit?

This may be called a Discharge Consent, an Exemption or a Permit. WCI will check the Environment Agency’s Public Register as part of the Home Buyers Drainage Survey report.

8. If the system is served by a drainage field. Do you know of any wells or boreholes for potable water nearby?

Drainage fields cannot be located within 50m of any well, spring or borehole that is used to supply water for domestic or food production purposes.

9. Have you experienced any issues with the system?

These could include backing up of drains, smells, a need to empty the system more frequently, blockages or wet patches on land over the drainage field.

10. Is there any history of problems especially during wet weather?

In the winter the groundwater sits closer to the surface and can prevent a drainage field working properly. Any rainwater connected into the wastewater treatment system could also cause problems including washing out the tank.



Please call us on 01984 623404 or get in touch via the Contact Form to talk to us about our Home Buyer’s Drainage Surveys.