For Solicitors & Estate Agents
Drainage Surveys for Off-Mains Property Sales
In short: if a sale involves a septic tank, sewage treatment plant or cesspit, Private Drainage UK can put your buyer or seller in touch with an independent local drainage specialist for a survey or compliance check. It's free to request and there's no obligation, and the specialist provides a written report that can be shared with everyone in the chain.
Why drainage holds up rural sales
A mortgage valuation or standard homebuyer survey doesn't assess a septic tank's condition or whether it meets the rules. The question usually comes up late, when the drainage answers on the seller's property information form are vague, or when a buyer's solicitor raises an enquiry about where the system discharges.
In England, small sewage discharges are covered by the Environment Agency's general binding rules. A septic tank must not discharge directly to a ditch, stream or other surface water. Where one does, the operator must replace or upgrade it, usually by fitting a sewage treatment plant or a drainage field. When a property is sold, the guidance says buyer and seller should agree who carries out that work as part of the sale. The seller must also tell the buyer in writing about the system, including a description of it, where its main parts are, and its maintenance records.
Finding out early, with a specialist's report, gives both sides facts to negotiate on instead of a last-minute retention or a renegotiation just before exchange.
What a drainage survey covers
- The type of system and where the tank and outlet are
- Its condition and capacity, and whether it's reasonably sized for the property
- Where it discharges to: a drainage field, soakaway, ditch or watercourse
- Whether it appears to meet the general binding rules, or needs a permit
- Access for emptying and any obvious maintenance issues
- A written report your client can share with you, the other side and the lender
For more detail, see our guide to septic tank surveys.
How referrals work
- You or your client make a request with the property postcode and what's needed.
- We introduce one independent specialist who covers that area, rather than passing details to several firms.
- The specialist contacts your client directly to arrange and quote for the survey.
- Your client receives the report and can share it with you and the other side.
Specialists are independent businesses, and your client contracts with them directly. See our specialist network and how we make money.
Guides you can send to clients
- Buying a house with a septic tank: what buyers should check before exchange
- Selling a house with a septic tank: what sellers need to tell a buyer
- Septic tank discharging to a ditch: the most common compliance problem
- Is my septic tank compliant?: a plain-English checklist
A note you can copy to clients
The property you are buying or selling is not connected to the mains sewer. A standard survey or valuation will not tell you the condition of the septic tank or treatment plant, or whether it meets the Environment Agency's rules. We recommend arranging a specialist drainage survey before exchange. You can request one free of charge, with no obligation, at privatedrainageuk.co.uk/get-help.
Questions from solicitors and agents
Does it cost my client anything to make a request? + −
No. Requesting an introduction is free and there's no obligation to proceed. Your client agrees the survey price directly with the specialist before any work is done. If the specialist goes ahead with the work, they may pay us a referral fee, which never changes the price your client is quoted.
Can I make the request on my client’s behalf? + −
Yes, as long as your client is happy for you to share their details. Use the form with the property postcode and your client's contact details, and mention in the notes that you're the solicitor or agent on the transaction. The specialist then contacts your client directly.
Who receives the survey report? + −
The report belongs to whoever commissions the survey, usually the buyer or seller. They can pass it to you, the other side's solicitor or a lender. If you need a copy, ask your client to arrange this with the specialist.
What if the survey finds the system doesn’t comply? + −
The report should say what's wrong and what would put it right, such as replacing a septic tank that discharges to a ditch with a sewage treatment plant, or installing a drainage field. Buyer and seller can then agree who pays as part of the sale. The specialist can quote for the work, but there's no obligation to use them.
Does this cover Wales and Scotland? + −
The general binding rules described on this page apply in England. Wales and Scotland have their own regulators and rules (Natural Resources Wales and SEPA). You can still make a request for a property there, and we will tell your client if we cannot help in their area.
Get Help
Have a client with private drainage?
Request a specialist drainage survey for a buyer or seller. It's free to ask and there's no obligation.