Drainage and Water Search Cost UK (2026)

What a drainage and water search is

A drainage and water search, known as the CON29DW, is a standard report your conveyancer orders when you buy a home. It draws on the local water and sewerage company's records to tell you how the property is supplied with water and how its waste water is dealt with.

It is one of the three core searches in a conveyancing pack, alongside the local authority search and the environmental search. On its own it is inexpensive, usually £40 to £75, but it answers questions that can be expensive to discover after completion.

What the search shows

• Whether the property is connected to the mains water supply and to the public sewer.
• Where public sewers, drains and water mains run, including any that cross the property.
• Whether a public sewer runs within the boundary, which can restrict where you build an extension.
• Who is responsible for billing and for maintaining the pipes.
• Whether the property is at risk of internal sewer flooding and whether the area is metered.

Who needs it

Most buyers using a mortgage will need one, because lenders expect the standard search pack. Cash buyers can technically skip it, but doing so means buying blind on drainage, which is rarely worth the small saving.

It matters most where a property has been extended, sits over or near a public sewer, or is in an area not on mains drainage. A property on a septic tank or private treatment plant has different obligations under the rules on private sewage, and the search helps flag this early.

Is it worth it

Yes. At £40 to £75 it is the cheapest of the core searches and it can surface build-over restrictions, shared drains, or a missing mains connection. Any of these can affect what you can do with the property and what it is worth.

The risk it protects against is real: discovering a public sewer under your planned extension after you have bought can stall or block the project, because building over or near a public sewer needs the water company's agreement.

How to triage cheaply before you pay

The full search pack of £250 to £450 is only ordered once you are committed to a property, usually after your offer is accepted and your solicitor is instructed. Before that point you can do a lot of free or cheap homework so you do not pay search fees on a property you walk away from.

HomeBuyerCheck gives a free instant report on any address covering sales history, EPC, flood risk from the Environment Agency, crime, schools and council tax. The £4.99 Premium report adds ground risk, radon, listed and conservation status, ownership from HM Land Registry, Companies House links, Building Safety Register and tribunal records, plus an AI buyer's verdict. Running that pre-offer means you only commit to the £250-plus search pack on a property you actually want.