What Is a CON29DW Report? The Drainage and Water Search Explained

A CON29DW report is the official drainage and water search a conveyancer orders during a property purchase. Compiled from the water company's own records, it answers 26 standardised enquiries about how a property connects to the public water and sewer network, who bills for those services, and whether the pipes running under or near the site carry any hidden risk. It is one of the core searches on almost every home purchase in England and Wales.

Because it maps what lies beneath a property rather than judging how likely that property is to flood, a CON29DW report is a starting point for due diligence, not the last word on it. Where a search throws up a drainage concern or a flood flag, buyers often follow it with an independent flood risk survey when buying a house. This guide explains what the report covers, what it reveals, what it leaves out, what it costs, and how to read the result.

Around 6.3 million properties in England sit in an area at risk of flooding, and 4.6 million of those are at risk from surface water: the drainage a CON29DW maps, but never assesses.

What does a CON29DW drainage and water search cover?

A CON29DW covers four things: where the public water and sewer pipes run, how the property drains, how it is supplied with water, and how it is billed. The Drainage and Water Searches Network groups its 26 enquiries under those four headings: Maps, Drainage, Water and Charging. Whichever water company produced it, every report answers the same set questions in the same order.

The drainage section does the heavy lifting. It confirms whether foul water and surface water leave the property through a public sewer or through a private arrangement, whether a public sewer or pumping station crosses the boundary, and whether the property appears on the water company's register of homes at risk of internal flooding from overloaded sewers. The water section confirms the mains connection, flags any main running under the plot, and records water hardness and pressure. The two maps put all of that on a plan, and the charging section sets out who bills for what.

• Standardised, not bespoke. The enquiries were developed with the Law Society, so a CON29DW from one region reads the same as one from another.
• Drawn from records, not a visit. Answers come from the water company's asset and billing data; no one inspects the property.
• Residential since 2002. The residential report has been in use since 2002; a commercial version followed in 2010.

What risks can a CON29DW report reveal?

The value of a CON29DW report is in the drainage problems it flags: the ones that are expensive or awkward to fix after completion. The most important are a public sewer running within the boundary, an unadopted private sewer, a history of sewer flooding, and drainage that never reaches a public pipe at all. Each one changes what an owner can build, what they will pay, or how easily the property will sell on.

• A public sewer within the boundary. If a public sewer crosses the plot, the water company has rights over it. Building an extension over or near it usually needs a build-over agreement, and the pipe can restrict where you build.
• Unadopted drains and sewers. Where sewers have not been adopted under a Section 104 agreement, their repair can fall to the owners they serve rather than to the water company.
• Sewer flooding history. Enquiry 2.8 shows whether the property is on the register of homes at risk of internal flooding from overloaded public sewers, a form of sewer flooding that national flood maps do not show.
• Private or surface-water drainage. If surface water does not drain to a public sewer, it is soaking away or running to a watercourse, which matters if you later change the hard surfacing or extend.
• A pumping station on the plot. A public pumping station within the boundary, or close to it, brings its own access and easement constraints.

A public sewer running under a proposed extension is one of the most common reasons a straightforward drainage search turns into a build-over agreement, a redesign, or a renegotiated price.

None of these findings is necessarily a reason to walk away. They are reasons to ask the next question: how the property connects, who owns the pipe, and what any future work would involve. Our explainer on foul, surface and combined sewers unpacks how those systems differ and why it matters.

CON29DW Residential vs Commercial: which report do you need?

There are two versions of the report. The CON29DW Residential covers the purchase of a home; the CON29DW Commercial, introduced in 2010, covers land and commercial property and adds enquiries that matter to a business occupier. Both are built on the same water-company records; the commercial report simply asks more.

For most buyers the residential report is the right one. If the purchase involves a site with development potential, the commercial report, or a fuller pre-development enquiry with the water company, gives the asset detail a scheme needs. Where drainage will shape a planning application, that work belongs in a compliant surface water drainage strategy rather than in a conveyancing search.

Official vs regulated drainage and water searches: which does your lender accept?

Not every drainage and water search is a CON29DW. There are two routes to the same information: an official search produced by the water company, and a regulated (or personal) search produced by a private search company from the same records. The difference matters most when a mortgage lender is involved, because the accuracy backing and lender acceptance are not the same.

A regulated search can be quicker and cheaper, but if your lender rejects it you pay twice, so confirm what the lender's instructions require before you order.

How much does a CON29DW report cost, and how long does it take?

A CON29DW report typically costs between about £56 and £85 including VAT, depending on the water company and the delivery speed, and it is usually returned within one to three working days. It is one of the cheaper and faster items in a conveyancing file. Severn Trent Searches, for example, reports that 97% of its residential CON29DWs are returned within one working day.

• Cost. Roughly £56–£85 inc VAT for a residential report, set by the water company rather than negotiated.
• Turnaround. Commonly 1–3 working days; often same or next day for the official electronic version.
• Who orders it. Your conveyancer or solicitor, as part of the standard search pack, and passes the fee on to you.

Set against the cost of discovering an unadopted sewer or a build-over problem after completion, it is a small, worthwhile spend, and that is why it appears on almost every purchase.

Do you need a CON29DW report when buying a house?

If you are buying with a mortgage, you effectively need one: most lenders require a drainage and water search under the industry's mortgage lending standards, so your conveyancer will order it as a matter of course. A cash buyer can decline it, but does so blind to everything the report would have flagged, which is rarely a saving worth making.

1. Your conveyancer orders the search alongside the local authority and environmental searches, early in the transaction.
2. The water company compiles it from its asset and billing records and returns the report, usually within a few days.
3. Your conveyancer reviews the result and raises anything material with you and the seller, whether that is a sewer within the boundary, an unadopted drain or a flooding flag.
4. You decide what the finding means for the price, the survey, or any further investigation before you commit.

That last step is where a clean-looking report and a flagged one part company. A flag is not a verdict; it is a prompt to understand the specific risk, which is where independent advice is worth having.

What a CON29DW report does not tell you: flood risk and planning

A CON29DW report tells you how a property drains. It does not tell you whether the property will flood, or whether a scheme will pass planning. It assesses no flood risk from rivers, the sea or surface water, it involves no site visit, and it carries no weight as planning evidence. The one flooding question it does answer, enquiry 2.8, is narrow: it reports the water company's record of internal flooding from overloaded public sewers, and nothing else.

That gap matters because surface water, the source a CON29DW never assesses, is the largest flood risk in England. A buyer whose search, survey or lender raises a concern needs property-level answers, which is the job of a flood risk survey for your property purchase, not a drainage search. It is also why a conveyancing flood report won't pass planning: a planning application needs a site-specific flood risk assessment for planning, and a development's drainage needs a full strategy. If you are still at the research stage, our guide to how to check flood risk before buying is the place to start, and sellers should note that the TA6 form now asks about flooding from any source.

So read the CON29DW for what it is: an accurate map of the water and drainage assets and their costs. Reach for a flood risk survey or a full drainage strategy when the question turns to safety or planning. If a search has flagged a concern on a property you are buying or a site you are developing, talk to our flood risk and drainage consultants for a clear, property-specific answer.

Frequently asked questions

The CON29DW is a well-designed, low-cost search that does one job well: it tells you how a property connects to water and drainage, and what those services cost. Read alongside a proper view of flood risk, it helps you buy, or build, with your eyes open. For the water-industry background, the Drainage and Water Searches Network is the report's official home, and the Water Industry Act 1991 and the government's check long-term flood risk service set out the wider legal and flood-risk framework.