Buying a House with a Septic Tank

Many people have concerns when buying a house with a septic tank - and rightly so.

Even properties with existing septic tanks, which have a Consent to Discharge, may now have to replace their sewage systems.

Failed septic tank soakaway

Septic Tanks were the old method of disposing sewage effluent and have been in existence for nearly 150 years. They are composed of 2 components:

Both these components are important, but it is the SOAKAWAY DRAINAGE FIELD that is the most important part of the system and the part most likely to be in trouble and require replacement. Soakaways have a limited lifespan, usually between 5 and 20 years, depending on the type of soil they are constructed in - sandy soil being the best and clay soils being the worst.

Most people who ring us simply assume that if the soakaway has failed, they can install a new one. This is NOT the case and the vast majority fail the mandatory soakaway tests. The rules on the construction of soakaways have changed in recent years and this also includes the replacement of existing soakaways. Before the year 2000 AD, soakaways were not even part of the Building Regulations, but in 2000 AD, Section H2 was created and this covers the rules and regulations for foul drainage soakaways.

In order to be certain that you CAN replace the soakaway, then your site has to have the following:

  1. Enough land to put a new soakaway in. All foul water soakaways must be in a new area of the garden away from any rainwater soakways, not under drives, parking areas or paths and at least 15 metres from any building and 2 metres from a boundary. As the average soakaway drainfield takes up at least 100M², you can see that you need a very big lawn to site a new one.
  2. A water table that NEVER gets to within 2 metres of ground level, even in a wet winter. 60% of sites in the UK fail this Trial Site Assessment Hole test.
  3. The correct type of soil, neither too sandy or too heavy. Another 60% of sites fail these Percolation Tests.
  4. A site that is NOT in a Groundwater Source Protection Zone. These zones were set up recently by the Environment Agency to protect drinking water abstracted from boreholes. If you are in Zone 1, then you cannot have a new soakaway.

If you fail either 2, 3 or 4, then you cannot have a replacement soakaway NO MATTER HOW MUCH LAND YOU HAVE and could end up with a house that has no sanitation possible.

Sometimes, the septic tank discharges into a ditch or stream. This is and always has been illegal and all such systems must be replaced with sewage treatment plants by 1st July 2020, or when the house is sold, if before that date, under the Government General Binding Rules 2015.

Buyer Beware!