2nd May 2019
We are so frequently contacted by people who are either selling a property or buying one and have been advised – rightly so – by their solicitors to “have a survey done” on the “septic tank” that we’ve put together the following list of questions to help you.
It’s very easy for solicitors to say “have the septic tank surveyed” but, unlike a house, practically nothing of the sewage treatment system can be seen above ground. A septic tank is always full to the level of the outlet pipe, so the internal structure cannot be seen unless the tank is empty. If the septic tank is fibreglass or plastic it may not be possible to see into the tank even when it’s empty because of internal baffles or a long extension neck. The treatment/drainage field that should come after the septic tank is underground, so to see its condition it has to be CCTV-ed. Unless there is an access point like a manhole or a rodding eye then you have to dig and break in to the tail drain leading to the treatment/drainage field. It may not be possible to CCTV the whole system as the CCTV camera head cannot be steered down one side or the other of any junction – it goes where it goes.
Before spending money emptying the septic tank, breaking in to the treatment/drainage field pipework and CCTV-ing it, all of which might cost £1000 or so plus VAT, getting the answers to the following questions from the property’s current owners and neighbours will tell you, and us, a lot.
- How many properties does the system serve? And how many bedrooms in each property? This will tell us how large any treatment/drainage field should be.
- Where is the septic tank and treatment/drainage field located? Or does the septic tank discharge directly to surface water, e.g. a stream? Does anyone have a plan of the system?
- On whose land is the system they located?
- What are the reported conditions/requirements for access? Then what do the property deeds say about the system, and access for inspection, maintenance and possible replacement?
- How old is the septic tank and treatment/drainage field? Who installed it? Are there any records from Building Control regarding the system meeting the Building Regulations of the time?
- What is the septic tank made of – brick, blocks, concrete, plastic, GRP? What is the maintenance record like?
- How often is the septic tank emptied, when was it last emptied and are copies of the Waste Transfer Notes available showing dates and the volumes taken?
- How is the system managed i.e. who decides when to empty the septic tank and how is payment apportioned – informally or formally through management company?
- Are there any wells or sensitive environmental areas nearby?
- Is there any history of problems especially during wet weather, when either the groundwater sits closer to the surface or rainwater gets into the wastewater treatment system?
- Is there any boggy or wet ground downslope of the septic tank? If there is, how much land is available for a new treatment/drainage field? For a 4 bedroom house, at best you'll need 50m of treatment'drainage field trench and, at worst, over 300m, in 30m lengths side by side by 1-2m between the trenches.
Once you have answers to these questions call us and we can arrange to do a visual inspection when we’re next in the area.