My Basement is Flooded — What Do I Do Right Now?

Step 1 — Turn off the electricity to the basement

Before you go near the water, go to your consumer unit (fuse box) and switch off every circuit that feeds the flooded area. If you're not sure which circuits cover the basement, switch off the main breaker entirely. Water plus live mains kills.

If the water has already risen above any sockets, cables, or the consumer unit itself — do not enter. Call the emergency line: 105 (power distribution) and then a qualified electrician.

Step 2 — Identify the source

Work out where the water is coming in. Four common culprits:

• Burst pipe — clean water, usually localised. Find the stop tap and shut off mains.
• Rising groundwater / storm surge — cloudy or dirty water, seeping through floor or walls. No stop tap fixes this.
• Drain backup — foul-smelling, often brown. Sewage — see step 5.
• Roof or gutter failure — water from above, following walls down. Check your gutters.

Step 3 — Stop the source if you can

For burst pipes, turn off the mains stop tap (usually under the kitchen sink or in the meter box outside). For overflowing rainwater, clear blocked gutters and downpipes if safe to do so. For drain backups — do not try to unblock yourself; call a drainage engineer.

If the source is groundwater, there is nothing you can do from inside. Move to step 4 and get a pump on site.

Step 4 — Document for insurance

Before you start cleaning up, take photos and videos of:

• Water level against walls
• Any damaged belongings, furniture, boxes
• Source of ingress if visible
• Damage to floors, skirting, walls

Then phone your buildings and contents insurer to log the claim. They'll usually approve emergency dry-out and pumping as long as it's documented.

Step 5 — Do not enter sewage water

If the water is brown, smells foul, or you know it's come from a drain — do not wade in. Contaminated water carries pathogens that cause serious gastrointestinal illness and skin infections. Keep pets and children well away. Call a professional restoration company who will arrive in full PPE.

Step 6 — Extract the water

Options, in order of speed:

1. Professional emergency pump-out — a specialist arrives with a petrol or high-flow electric pump. Clears a typical basement in 30–90 minutes. £200–£500 callout plus hourly labour.
2. Wet/dry vac — OK for small puddles (under 5 cm), but slow and you'll be there all day for anything deeper. Most hire shops rent industrial units for £30–£50/day.
3. Submersible utility pump — £80–£200 to buy, clears water at 50–100 litres per minute. Worth buying if you have recurring flooding.

Step 7 — Dry out properly (takes longer than you think)

Water leaves the floor in hours. Walls, plaster, insulation, and substrate can take 2–6 weeks to dry fully — even when they look dry on the surface. Skip this step and mould is guaranteed within 48 hours.

Proper drying kit:

• Industrial dehumidifier — £20–£50/day to hire. Run continuously for at least 7 days.
• Air movers (axial fans) — drive airflow across damp surfaces to speed evaporation.
• Moisture meter — check readings weekly. Don't redecorate until plaster reads below 15%.

Prevention — so this doesn't happen again

Once the immediate emergency is handled, you need to address the reason the basement flooded. A one-off pump-out costs £500. A permanent solution costs £3,000–£8,000 — and pays for itself the first time a big storm hits and your basement stays dry.

Permanent solutions, matched to cause:

• Rising groundwater → sump pump system + cavity drain membrane
• External water pooling → French drain + re-grading ground away from foundations
• Rising damp through walls → chemical DPC injection + cavity drain
• Drain backup → non-return valve on the soil pipe + sump pump

Related reading

• 7 Signs You Need a Sump Pump
• Sump Pump vs French Drain — Which Does My Basement Need?
• How Much Does Basement Waterproofing Cost in the UK?