Property Transactions
Private Drainage Survey
An independent assessment of a septic tank, treatment plant or cesspit — covering type, age, condition, capacity and compliance — typically arranged during a property purchase or sale.
In short: a private drainage survey is the off-mains equivalent of a damp survey or a structural survey — a focused, specialist assessment of a specific system that a general property survey won't cover in any useful depth.
When to arrange one
- Buying a property with a septic tank, treatment plant or cesspit — see buying a house with a septic tank
- Selling a property, to get ahead of anything a buyer's own survey might flag
- Suspecting a problem without an obvious cause
- Before extending a property or changing its use, where occupancy will increase
What's covered
A private drainage survey typically assesses system type and age, physical condition, drainage field performance, discharge arrangement and likely compliance position, and capacity relative to the property's occupancy. See our related guide on the septic tank survey process for more detail.
What you receive
A written report of findings and, where relevant, recommendations. This is professional guidance rather than a legal or regulatory determination — where compliance is in question, the report will typically point to next steps rather than a definitive ruling.
Is a private drainage survey the same as a septic tank survey? + −
Yes — 'private drainage survey' is the broader term covering septic tanks, treatment plants and cesspits, while 'septic tank survey' is often used specifically for the most common system type.
How long does a private drainage survey take to arrange? + −
Most specialists can typically schedule a domestic survey within a week or two, though this varies with location and demand.
Can I get a private drainage survey without buying or selling? + −
Yes — many homeowners arrange one simply to understand a system they've inherited or suspect has a problem.
Arrange Your Survey
Arrange a private drainage survey
We'll help you find an appropriate independent specialist to carry out the survey.