Killing the Sewer Smell Under the Kitchen Sink with Gap Putty

Not strictly woodworking DIY, but I solved the under-sink sewer odor in our kitchen using putty. Sharing in case it’s useful.

The problem
When I’d open the under-sink drawer, there was a faint sewer-pipe smell.
(It wasn’t strong, so I’d been ignoring it for a long time.)

I tried a pipe drain cleaner first — no effect.
The smell was faint, so a disconnected pipe seemed unlikely. My guess: sewer odor was leaking up through some small gap.

Pulled out the drawer.
Underneath there are just three pipes coming through the floor — if I seal the gaps around all of them, the smell should be sealed off.

Of the three pipes, the left two are hot and cold supply, and the right one is the drain (connected to sewer).
I held my nose close to each one but the smell was too faint to localize the source.

So I went with: just seal every pipe penetration, doesn’t matter which.

I used “gap putty” (sukima-pate) — a non-hardening putty that you can shape like clay.

Pack putty into the gap around the drain pipe.

Sealed the upper seam too.

Just to be safe, I also puttied around the two non-drain (water supply) pipes.

Done!

Result?

⇒ The faint sewer smell is gone!