The Property Search
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What’s screened

Sewer and drainage flooding

When sewers can’t cope, they back up into homes and gardens. It’s a real risk the national flood maps don’t show.

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About this data

What it is
Flooding from foul or surface-water sewers that back up in heavy rain or through a blockage. Water can come up through gullies, drains and low-level toilets, or pond in gardens and roads.
Why it isn’t mapped
Sewer records and flooding history are held by the water and sewerage company, not published as open data. The national flood maps don’t show it.
What the report shows
The sewerage undertaker for the property, so you know who holds the records, and a clear note that sewer flooding is not scored. It is never folded into the overall flood rating.
Sample report page covering groundwater, source protection and sewer flooding
How the sample report handles sewer and drainage flooding.

How to find out more

The drainage and water search. Your solicitor’s drainage and water search (CON29DW) confirms whether the property drains to public sewers and whether sewers run under the plot.

The water company. Water companies keep records of properties that have flooded internally from their sewers. Some will confirm whether a property is on that record if you ask.

The seller. The property information form asks about past flooding. Ask specifically about sewer or drain back-up.

Signs worth noticing on a viewing

  • Floor levels at or below the road
  • Basements or cellars
  • Non-return valves or anti-flood toilet fittings
  • Staining on garden walls or at the base of doors

Questions we get asked

Is sewer flooding covered by the flood maps?

No. The Environment Agency maps cover rivers, the sea, surface water, reservoirs and groundwater susceptibility. Sewer flooding records sit with the water company.

Who is responsible for a sewer under my garden?

Most shared sewers serving more than one property belong to the water company. A drainage and water search shows public sewers near the property.

Does home insurance cover sewer flooding?

Many policies do, but terms vary. Check the policy wording for escape of water and flood.

One address, one clear report

See the flood & environmental picture for your property

Every open flood source, plus ground, environment, value and context — a plain-English PDF report for the exact plot you draw, for £20.

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