Buying & Selling
Septic Tank Survey
What a septic tank survey involves, when you need one, and what to do with the results.
In short: a septic tank survey is a targeted inspection of a private drainage system — usually carried out as part of a property purchase, sale, or when a problem is suspected — covering type, age, condition, capacity and compliance.
When you need one
- Buying a property with private drainage — see buying a house with a septic tank
- Selling a property, to identify issues before they surface in a buyer’s own survey
- Suspecting a problem (smells, slow drainage, wet ground) without a clear cause
- Planning an extension or change of use that could affect system capacity
What’s inspected
- Tank type, approximate age and physical condition
- Drainage field location and apparent performance
- Discharge point and likely compliance position under the General Binding Rules
- Signs of previous repairs, damage or inadequate capacity
- Available documentation (installation records, emptying receipts, permits)
What you get afterwards
A written report setting out findings and, where relevant, recommendations — which might range from “no action needed” through routine maintenance advice to a recommendation for replacement or further assessment. This is general guidance, not a legal or regulatory determination — see our compliance checker for a quick self-assessment starting point.
How long does a septic tank survey take? + −
A typical domestic survey takes a few hours on site, depending on system accessibility and complexity.
Does a septic tank survey involve digging up the tank? + −
Not usually for a standard visual and functional survey — access is normally through existing inspection points. More invasive investigation is occasionally needed for unclear cases.
How much does a septic tank survey cost? + −
See our septic tank survey cost guide for an indicative range — cost depends on property size, system type and location.
Sources
- British Water — Code of Practice: Septic tanks and treatment plants