Plumbing 19 October 2026

House Flooded? What to Do in the First Hour, and Why Tonbridge Homes Near the Medway Should Plan for It

If your house is flooding right now, the order is people, power, gas, water, then everything else: get anyone vulnerable upstairs or out, switch the electricity off at the consumer unit if it is dry and safe to reach, turn the gas off at the meter only if the meter is not under water, and if the water is coming from inside the house shut the stopcock. Only once those four things are done is it worth thinking about carpets, insurers or the boiler.

That is true anywhere in Kent, but Tonbridge town centre sits on the floodplain of the River Medway, and the river has come into people’s homes within living memory more than once. This guide covers the first hour, what water does to a boiler and heating system, and what a household near the river can do before winter. If you need an engineer once the water has gone down, call us on 01732 792 454.

My house has flooded, what do I do first?

Whether it is the river or a burst pipe, the first ten minutes go the same way:

1. People first. Keep children and pets out of standing water and move anyone who cannot easily get upstairs.
2. Electricity off, if you can do it dry. If the consumer unit is above the water and you can reach it with dry hands from a dry surface, switch the main switch off. If you would have to wade to it, leave it and call your electricity network operator on 105.
3. Gas off, with one exception. If the emergency control valve by the meter is above the water, turn it a quarter-turn to off. If the meter is under water or in a flooded cellar, do not touch it. If you smell gas at any point, call the National Gas Emergency Service on 0800 111 999.
4. Find the source. Water coming up through the floor, under the doors or out of the drains is the river or the sewer, and nothing inside the house will stop it. Water pouring from a ceiling or a cupboard is your plumbing, and the stopcock will stop it. Our guide to water leaking through the ceiling covers that case step by step.
5. Photograph everything before you move it. Your insurer will want pictures and a list, and our post on claiming on home insurance for a water leak explains what a plumber’s report can and cannot say for you.

Is it the river or a burst pipe?

The fixes are completely different. A burst pipe is a plumbing emergency: shut the stopcock, open the taps to drain down, and call a plumber. The water is clean and the damage stops the moment the supply is off. In a cold snap the usual cause is a frozen pipe in a loft or outbuilding that has split and thawed, which we covered in our post on frozen pipes in Crowborough; our emergency plumbers page explains how our out-of-hours cover works.

River flooding is different in three ways. You cannot turn it off. The water is contaminated, often with sewage from surcharged drains. And it comes up from below, so it reaches everything that lives at floor level: floor-standing boilers, ground-floor cylinders, under-floor pipework, sockets and low-mounted consumer units.

Why Tonbridge has to take this seriously

Tonbridge grew up around a crossing of the Medway, and a good deal of the town either side of the river sits on the floodplain. The Environment Agency’s own history of the catchment lists serious floods in 1968, 2000 and 2013, and notes that a significant flood happens on the Medway roughly every fifteen years.

Two things have been built to deal with that. The first is the Leigh Flood Storage Area, completed in 1982 a couple of miles upstream: a 1.3 kilometre embankment across the valley with three steel gates that hold a flood peak back on the meadows and release it slowly. It has been used 75 times since 1981.

The second is recent. Over Christmas 2013 up to 76 millimetres of rain fell in 24 hours on a saturated catchment, the storage area filled, and the river came over the bank at Avebury Avenue; approximately 80 homes in the Barden Road and Danvers Road area were flooded. The Environment Agency later built a 320 metre defence behind Avebury Avenue, and at the end of September 2026 it opened a much larger scheme: the Leigh storage area is around 23 per cent bigger and Hildenborough has a new embankment and pumping station, which the Agency says reduces flood risk to 1,870 homes and 575 businesses.

None of that means the risk has gone; it means the river is managed. Anyone within reach of it should check their address on the government’s flood information service and sign up for free flood warnings (Floodline is 0345 988 1188). We are based in Tonbridge ourselves; our Tonbridge plumbing and heating page covers what we do here.

What happens if my boiler gets wet?

You do not find out by switching it on.

A modern gas boiler is full of electronics: a circuit board, a fan, a gas valve, sensors and a pump. Water in any of them is an electrical fault waiting to happen, and water in the gas valve or burner compartment is a safety fault. A boiler that was submerged, or had water running down the wall behind it, must be treated as unsafe until a Gas Safe registered engineer has inspected it. Water-damaged gas appliances can leak, burn badly and produce carbon monoxide, and the fault does not always show on day one.

Floor-standing boilers, back boilers and boilers in ground-floor utility rooms are the ones that get caught. A wall-hung combi will usually escape a shallow flood, but its condensate trap and the pipework below it will not. The rest of the system needs the same care: a ground-floor cylinder has its immersion heater and thermostat at low level, a submerged heating pump will run for a while and then seize, and low-mounted thermostats and wiring centres need checking before anything is powered up.

Our engineers inspect a flooded appliance with the power and gas off first, then test it in a sensible order. Diagnosis is charged at our normal rate of £95+VAT for the first hour and £47.50+VAT per 30 minutes after that, and anything on the gas side is only ever done by a Gas Safe registered engineer. Where a boiler is beyond saving we will say so, and a replacement boiler comes with a free fixed written quote; see our boiler breakdowns and repairs page for how we work.

Drying out and getting the heating back on

A flooded ground floor can take weeks to dry, and running the heating is part of that, so we try to get a safe appliance going quickly. Before it goes on, have the electrics inspected by an electrician and the gas appliances by a Gas Safe engineer. If the water came up through the drains, the outside gullies may be full of silt; our post on blocked drains outside the house explains whose drain is whose. Any cold water tank or cylinder that floodwater reached should be drained, cleaned and refilled before use. Then dry the house steadily, windows open and heating low and constant.

If you live near the river, a few things worth doing now

• Sign up for flood warnings and know the difference: a flood alert means be ready, a flood warning means act.
• Know where your stopcock, consumer unit and gas emergency control valve are, and make sure everyone in the house can find them in the dark.
• Look at where the kit lives. If you are replacing a boiler in a house that has flooded before, moving it to a wall or upstairs is worth discussing, and we will include it in the quote if it is practical.
• Get the system serviced before winter. A boiler service with us is £95+VAT, and it is the moment to check the condensate pipe, the flue and the pressure relief discharge, all of which are exposed in a flood.

If your home has been flooded, or you want advice on protecting a house near the Medway before the winter, call Plumbing Angels on 01732 792 454. We are Gas Safe registered, Tonbridge based, and we will tell you honestly what can be saved and what cannot.