What to do when your drain overflows at midnight

It is late, water is on the floor, and every instinct says to do something immediately. Most of those instincts make it worse. Work through this in order.

First: stop adding water

1. 1Stop using every fixture in the property, not just the affected one. All of them drain to the same line.
2. 2Stop any running appliance mid-cycle — a dishwasher or washing machine will empty into the blocked line without asking.
3. 3If a toilet is overflowing, shut the supply valve on the wall behind it, or lift the cistern lid and hold the flapper closed.
4. 4If water is coming up through a floor drain, that is the main line. Nothing indoors will fix it. Stop and call.

Second: contain and protect

• Towels and buckets. Anything to keep water off carpet, subfloor and into a hard-floored area
• Move what you can lift, particularly electricals and anything with a fabric base
• If it is sewage, keep children and pets out of the room entirely
• Ventilate if you can do it safely

Third: photograph it

Before you clean anything, take photographs and a short video. If this becomes an insurance claim, the evidence of the original extent is worth far more than a tidy room. Get wide shots and close-ups, and make sure the timestamps are on.

Fourth: call

We answer at any hour. On the call, the useful things to be able to say are: which fixtures are affected, whether anything is still actively overflowing, whether you know where your cleanout is, and whether you are on town sewer or septic. That last one changes the truck we send.

If you are on septic and everything in the house went slow at once, there is a reasonable chance the tank is full rather than the line blocked — which is a pump-out, not a drain clearing.