Is a blocked drain an emergency? What to do right now
Updated 3 July 2026
A slow drain is annoying; a fully blocked one that's backing up sewage or flooding is an emergency. Here's how to tell the difference and what to do.
When it's an emergency
Treat it as urgent if wastewater or sewage is backing up into sinks, baths or toilets, if multiple drains are blocked at once (a sign of a main drain problem), or if there's a risk of flooding inside the property.
Stop using water in the affected part of the house to avoid making the backup worse.
What you can try
For a single slow sink or toilet, a plunger or drain rods sometimes clear it. Avoid pouring caustic chemicals down repeatedly — they can damage pipes and rarely fix a serious blockage.
If it's more than one drain, or water is rising, don't keep trying — you likely have a blockage in the main drain that needs professional equipment.
Get help fast
FixDelivered finds a qualified local plumber who can clear the blockage, checks their fee and arrival time, and confirms one for you — with the callout fee shown upfront.
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Get help now →Frequently asked questions
Is a blocked drain an emergency?
It is if sewage is backing up, multiple drains are blocked, or there's a flood risk. A single slow drain usually isn't urgent.
How much to unblock a drain?
A straightforward unblock is typically £80–£150; jetting or a CCTV survey for a main-drain blockage costs more. Agree the price before work starts.
Should I use chemical drain cleaner?
Sparingly at most. Repeated use can damage pipes and rarely clears a serious blockage — rodding or jetting is more effective and safer.