Emergency Drain Clearance: What to Do When Your Drain Overflows

Sewage backing up into your shower. A manhole overflowing across the patio. Foul water rising in the downstairs toilet. A drain emergency is stressful, unpleasant, and often happens at the worst possible time — late on a Friday evening or Christmas morning. This guide covers exactly what to do, step by step, to contain the damage and get it fixed as quickly as possible.

Immediate Steps: The First 15 Minutes

Before you phone anyone, take these actions to limit the damage:

1. Stop using water. Don't flush toilets, run taps, or use the washing machine. Every litre of water you put into the system has nowhere to go and will make the overflow worse.
2. Turn off the washing machine or dishwasher if either is mid-cycle. These pump large volumes of water into the drain in short bursts and can rapidly escalate an overflow.
3. Contain the flooding. If sewage is backing up indoors, use old towels, bin bags, or plastic sheeting to contain it. Move furniture, rugs, and electrical items away from the affected area. If possible, open windows for ventilation — sewage gases are unpleasant and in confined spaces can cause headaches and nausea.
4. Keep children and pets away. Sewage contains bacteria including E. coli and other pathogens. The overflow area should be treated as contaminated until it's been cleaned and disinfected.
5. Take photos. Before you clean anything up, photograph the flooding from multiple angles. If you need to make an insurance claim later, visual evidence of the extent of the damage is essential.
6. Check external manholes. Carefully lift the nearest manhole cover (they're usually in the back garden or side passage). If the chamber is full of water, the blockage is downstream of that point. If it's empty, the blockage is between the house and that manhole. This information helps the engineer when they arrive.

How to Find Emergency Help Fast

In a drain emergency, speed matters. Here's the most efficient way to get someone out:

1. Check if it's your responsibility. If the overflowing manhole is a shared drain serving multiple properties (common on terraced streets and housing estates), it's your water company's responsibility. Call their 24-hour emergency line — this service is free. Thames Water, for example, aims to attend sewer emergencies within 4 hours.
2. Check your home insurance. If you have home emergency cover (included in many policies or available as an add-on), your insurer will arrange and pay for the call-out. Check your policy documents or call their claims line. Common providers like Aviva, Direct Line, and HomeServe cover drain emergencies up to £500 per incident.
3. Call a local drainage company. If the drain is your responsibility and you're paying out of pocket, search for companies that specifically advertise emergency or out-of-hours service. Many drainage companies operate 24/7 — look for those in your area with good reviews and confirmed availability.

When you call, tell them: what's happening (overflow, backup), which fixtures are affected, whether you've checked the manhole, and how urgent the situation is. The more information you give, the better equipped they'll arrive.

Typical Response Times

For a genuine emergency (sewage inside the house or an actively overflowing manhole), most drainage companies aim to arrive within 1–2 hours during working hours and 2–4 hours outside of working hours. In our experience, the average response time for an emergency call-out across England is around 90 minutes.

Response times are slower in rural areas where companies may need to travel further, and during periods of heavy rainfall when demand spikes. January and February are the busiest months for emergency drain call-outs — a combination of ground movement from winter temperatures and increased water table levels.

What Happens During an Emergency Call-Out

Here's what to expect when the engineer arrives:

1. Assessment. The engineer will inspect the manholes, check which fixtures are affected, and identify where the blockage is. This usually takes 10–15 minutes.
2. Jetting. In most cases, the blockage is cleared using a high-pressure water jetting machine. The engineer feeds a hose with a specialised nozzle into the pipe from the nearest manhole and jets in the direction of the blockage. For a standard residential blockage, this takes 20–40 minutes.
3. Testing. Once the blockage is cleared, the engineer will run water through the system to confirm everything is flowing freely. They'll flush toilets and run taps to verify.
4. Advice. A good engineer will tell you what caused the blockage (grease, wipes, roots, etc.) and whether any follow-up work is recommended. If they suspect structural damage, they may suggest a CCTV survey as a separate visit.

The whole process typically takes 45 minutes to 1.5 hours from arrival to completion.

Emergency vs Standard Pricing

Emergency call-outs cost more than standard bookings. Here's what to expect:

The premium reflects unsociable hours, engineer availability, and the need for rapid response. If the situation isn't actively worsening — for example, the manhole is full but not overflowing and you can avoid using the drains overnight — waiting until standard hours could save you £50–£100. But if sewage is entering your home, don't wait.

Making an Insurance Claim

If the drain overflow has caused damage to your property, your buildings or contents insurance may cover the cost of repairs (though not usually the drain clearance itself). To give yourself the best chance of a successful claim:

• Document everything. Take photos and video before cleaning up. Include wide shots showing the extent of flooding and close-ups of damaged items, flooring, walls, and skirting boards.
• Keep receipts. The drain clearance invoice, any cleaning products purchased, and any emergency purchases (replacement towels, temporary flooring, etc.) are all relevant.
• Ask the drainage company for a written report. This should describe what they found, what caused the blockage, and what work was carried out. Many companies provide this as standard.
• Notify your insurer promptly. Most policies require you to report a claim within a set period (typically 30 days for damage claims). Call the claims line the day after the emergency if possible.
• Don't discard damaged items until the insurer or their assessor has seen them or told you it's fine to do so.

After the Emergency: Preventing a Repeat

Once the immediate crisis is resolved, it's worth understanding why it happened so you can prevent a recurrence. The most common causes of drain emergencies are:

• Fat and grease build-up — accumulates over months and then blocks suddenly when a piece breaks off and lodges at a joint or bend.
• Wet wipes and sanitary products — the single most common cause of toilet and soil pipe blockages. Even wipes marketed as “flushable” don't break down in drainage systems.
• Tree root ingress — roots seek out moisture and can penetrate clay pipe joints. If roots were the cause, the engineer may recommend a CCTV survey and possibly root cutting or pipe repair.

For detailed prevention advice, see our guide on how to prevent blocked drains.