From DIYWiki
Jump to navigation Jump to search

Flooding can cause considerable damage to both bouse and posessions. Floodwater from river overflow carries raw sewage and dirt, and makes a house uninhabitable until remedial works have been carried out.

Some types of flooding are preventable.


  • River Overflow
  • Basement Flooding
  • Washing Machine
  • Plumbing Leak
  • Blocked soil pipe collapse
  • Bath Overflow
  • Cistern Overflow

Flood Risk Assessment

A search should reveal any history of flooding.

Insurer's flood risk ratings may be unreliable, as insurers tend to assess risk by postcode, and not all houses are at the same level in any one postcode area.

When purchasing, is your house on a flood plane?

Flood Risk assessment & advice page


River Overflow

Obviously houses on flood planes can be expected to flood. Houses close to water level eg on a river bank may too.


To resolve a repeat flooding problem, it is sometimes possible to construct banks around a property. These are a little inconvenient, but can turn a regularly flooded house into a dry one. Rubble may be mixed in with the earth. The banks can be planted and grassed to maximise strength and avoid erosion, or other means may be used such as concrete walls, gabions, or stones laid on the surface of earth banks.

A foul water pump, generator & fuel should also be kept on the property.

Unfortunately constructing earth banks around a property is not practical in most cases.

Minimising Damage

Another approach is to minimise the damage done by flooding. To minimise damage and make clean up easier:

  • Tiled floors and lower walls
  • Keep all electrics above the flood level
  • Keep a source of backup power
  • Mount TV and as many other goods as possible above flood level
  • Easily washed goods make cleanup after a flood easier, so plastic & metal rather than raffia etc.
  • Store paperwork upstairs
  • A generator, fuel, foul water pump & pressure washer will enable rapid cleanup of soiled goods, tiled floors, etc
  • Where practical, a raised parking pad can keep a parked vehicle out of flood water
  • Keep flood supplies upstairs

Basement Flooding

Basements prone to occasional flooding may be kept clear by an automtic pump in a sump, aka a hole in the floor. The pump comes on only when it detects water.

Pumps don't last forever, and will fail sooner or later. A backup water alarm is a good idea.

For properties on a hillside, installing ground drainage to divert water coming down the hill around the house is another option.

Washing Machine

Descale the machine from time to time to avoid build up of scale which blocks the level sensor tube, and causes floods.

Many machines will permit the door to be opened even when the water level is high enough to flood. Be aware of this if a machine doesn't finish its wash cycle.

Plumbing Leak

Mending minor leaks promptly can reduce the risk of a full bore blowout.

Lagging pipes exposed to freezing conditions can reduce the chance of a freeze burst.

Blocked soil pipe collapse

Unsupported runs of pushfit soil pipe may work ok, but when filled by a blockage and then rodded can collapse, with unsavoury results.

Bath Overflow

Not leaving the bath unattended while filling is the obvious solution.

There are overflow preventing devices available, but the cost is not normally considered worthwhile outside of special accommodation for people with problems.

Cistern Overflow

Toilet cistern, central heating header tank and hot water header tank should all have a working overflow pipe.

See Also