A CON29DW drainage and water search tells you everything about the water supply and sewerage arrangements for a property — including whether sewers run through the land, where the stopcock is, and which company supplies the water.
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Key Points
The official form is the CON29DW — issued by the relevant water company (e.g. Thames Water, Severn Trent)
Reveals whether sewers pass through or under the property — which can block building works
Cost: approximately £35–£75 as a disbursement in your conveyancing quote
Turnaround: typically 3–10 working days from the relevant water authority
Required by all mortgage lenders as standard
What Does a Drainage and Water Search Reveal?
The CON29DW contains up to 23 standard enquiries covering four broad areas of concern for buyers:
💧 Water Supply
Is the property connected to the public water supply?
Where is the stopcock located?
Are any water mains located within the boundary?
Who is the water supplier?
Is there a water meter?
🚽 Drainage & Sewerage
Is the property connected to public sewers?
Do public sewers pass through or under the property?
Is there a septic tank or cesspit?
Are there any sewage treatment plants within 50m?
Who is the sewerage undertaker?
Why Does It Matter if a Sewer Runs Through Your Land?
This is one of the most practically significant results in the search. If a public sewer passes through or under the property:
You cannot build over or close to it without permission from the sewerage authority
Any extension, outbuilding, or patio covering the sewer may need to be relocated at your expense
The sewerage company has a right of access to maintain or repair the sewer, potentially crossing your garden
Some mortgage lenders will request a build-over agreement if an existing structure is already over a sewer
This is particularly relevant if you're buying with plans to extend. Always check the sewer map before finalising your building plans.
Not Connected to the Public Sewer: What Then?
Around 3–4% of properties in England and Wales are not connected to the public sewer system. This is common in rural areas. Instead, they use:
🪣
Cesspit
Simply a sealed storage tank. No treatment — must be pumped out regularly (typically every 6–8 weeks). Running cost: £100–£300 per pump-out.
🌱
Septic Tank
Partially treats waste before discharging to a soakaway. Requires annual desludging (~£150–£300) and must meet Environment Agency discharge rules.
⚙️
Sewage Treatment Plant
Fully treats waste to a standard that can be discharged to a ditch or watercourse. More expensive to install (~£5,000–£15,000) but lowest ongoing costs.
If you're buying a property with its own sewage system, your solicitor should raise additional enquiries about the system's age, condition, capacity, and compliance with the 2020 Septic Tank Regulations.
Cost and Turnaround Times
Water Authority
Typical Fee
Turnaround
Thames Water (London & Home Counties)
~£60
5–10 working days
Severn Trent (Midlands)
~£45
3–7 working days
Yorkshire Water
~£40
3–7 working days
Anglian Water (East England)
~£55
5–10 working days
Southern Water
~£50
3–8 working days
Fees vary by water company, not by property value. The search is typically ordered at the same time as other conveyancing searches — after your offer is accepted and you've instructed a solicitor.
The Full Picture: All Conveyancing Searches Together
Search
What It Checks
Typical Cost
Required?
Local Authority (LLC1 + CON29)
Planning, roads, enforcement
£50–£300
Always
Drainage & Water (CON29DW)
Sewers, water supply
£35–£75
Always
Environmental
Contamination, flood, radon
£35–£100
Always
Coal Mining
Mining subsidence risk
£40–£60
If in mining area
Chancel Repair
Liability to repair church chancel
£15–£25
If in affected parish
Compare Conveyancing Quotes
Search costs including drainage and water are built into every quote. Compare regulated solicitors with full cost transparency.
Can I view the sewer map myself before making an offer?
Yes — many water companies provide a public sewer map viewer online. Thames Water, Severn Trent, and others publish these. However, the official CON29DW search provides a formal, certified record that your solicitor and lender can rely on legally.
What happens if my property already has a structure over a public sewer?
The seller's solicitor should provide a build-over agreement (previously issued by the sewerage authority), or obtain retrospective approval. Without this, some lenders may decline the mortgage. Your solicitor will raise a requisition on this point.
Is the drainage search the same as the environmental search?
No — they are separate searches. The drainage and water search (CON29DW) focuses specifically on water supply and sewerage infrastructure. The environmental search covers contaminated land, flood risk, and ground stability. Both are typically ordered together as part of your standard search pack.
What if the property is in Scotland or Northern Ireland?
Scotland uses a different legal system and different searches apply. In Scotland, water searches are handled differently through Registers of Scotland and Scottish Water. In Northern Ireland, the Water Service (NI Water) carries out equivalent checks. Your local solicitor will advise on the appropriate searches for your jurisdiction.