My bathroom sink has been slow-draining for — honestly, I do not even know how long. Long enough that I just accepted that brushing my teeth meant standing in a small puddle of toothpastey water. I got used to it. That is how these things go. You adapt to something dumb because fixing it sounds like work.

Why Baking Soda and Salt

This is not the baking soda and vinegar trick (that one is for freshening and minor gunk — it creates fizz but not a lot of scrubbing power). Salt adds abrasiveness. When you combine coarse salt with baking soda and flush it with boiling water, the salt crystals act like tiny scrubbers as they wash down the pipe, physically scouring the sludge off the pipe walls.

The baking soda deodorizes and breaks down greasy residue. The salt scrubs. The boiling water melts soap scum and carries everything away. Together they tackle the most common cause of slow bathroom drains: soap scum mixed with hair and toothpaste buildup.

The Method

1. Pour half a cup of baking soda down the drain. Tap the sink to knock it down into the pipe.
2. Pour half a cup of table salt (or coarse salt — kosher salt works great) right on top of the baking soda.
3. Let it sit for at least 30 minutes. Overnight is better. The salt and baking soda need time to work into the gunk. I usually do this before bed.
4. Boil a full kettle of water. Pour it down the drain in two stages — half first to activate the mixture, wait 30 seconds, then the rest to flush everything through.
5. Run hot tap water for a minute to make sure the drain is flowing.

When This Works vs When It Does Not

This works for slow drains — the kind where water still goes down but takes its time. If the drain is completely stopped, you need physical removal (plunger, snake, or removing the P-trap — see the other drain article in this batch).

It also works better on bathroom sinks and tubs than on kitchen sinks, because kitchen clogs are usually grease-based and need more aggressive treatment. For a kitchen slow drain, try the baking soda and vinegar method first (the fizzing helps with grease), then follow with this salt-and-boiling-water flush.

Do not use this if you have already poured chemical drain cleaner down recently. The chemical residue can react with baking soda and produce dangerous fumes. If you recently used Drano or similar, wait a few days and flush the drain thoroughly with water before trying anything else.

Monthly Maintenance

Once the drain is flowing again, I do a quick version of this once a month: a few tablespoons each of baking soda and salt, let it sit for 10 minutes, flush with a kettle of hot water. Takes less than two minutes of actual effort. Prevents the slow-drain from ever coming back.

I can brush my teeth without standing in a puddle now. The bar for home improvement satisfaction is surprisingly low.