2 bathrooms on the top floor , back up and flood out of the shower drain when either is used, eventually the water subsides.

Poured a few bottles of thai type Drano down them , does not work at all.

Not sure why the water is backing up as if there was a clog the Drano would have broken it up ?

Any suggestions ?

Do plumbing snakes exist here ?

Has it always done this for you, or is it something new? It matters because if it's always done it, say it's a new building, it could be a stack venting issue. If it's a new problem, you probably do need a snake. I've seen them but can't remember where. Price is cheap, maybe 600 - 700 baht??

Plumbing snakes available at any hardware store.

Has it always done this for you, or is it something new? It matters because if it's always done it, say it's a new building, it could be a stack venting issue. If it's a new problem, you probably do need a snake. I've seen them but can't remember where. Price is cheap, maybe 600 - 700 baht??

Say within the last 3 weeks recently , progressively worse even after the Drano , have asked my kids if they stuck anything down the shower hole , they said no.

Is your house fairly new, or been remodeled? I bought a new house and had occasional slow drain issues in the showers. Solved the problem by modifying the drain cover -- mine had a 1/2 sphere screwed to the underside, and I just removed that 1/2 sphere to result in only the flat drain cover plate remaining. Flowed freely ever since.

Is your house fairly new, or been remodeled? I bought a new house and had occasional slow drain issues in the showers. Solved the problem by modifying the drain cover -- mine had a 1/2 sphere screwed to the underside, and I just removed that 1/2 sphere to result in only the flat drain cover plate remaining. Flowed freely ever since.

Lol, I had the exact same issue in my new built.

Is your house fairly new, or been remodeled? I bought a new house and had occasional slow drain issues in the showers. Solved the problem by modifying the drain cover -- mine had a 1/2 sphere screwed to the underside, and I just removed that 1/2 sphere to result in only the flat drain cover plate remaining. Flowed freely ever since.

Drain covers came off well before it started getting worse.

Now trying to find a competent plumber.

Is your house fairly new, or been remodeled? I bought a new house and had occasional slow drain issues in the showers. Solved the problem by modifying the drain cover -- mine had a 1/2 sphere screwed to the underside, and I just removed that 1/2 sphere to result in only the flat drain cover plate remaining. Flowed freely ever since.

Not that it probably matters a whole lot, but by removing that 1/2 sphere you have removed the equivalent of a P-trap from that drain. It is designed so that water remains in a "moat" ringing the drain pipe opening, and that 1/2 sphere would rest in the moat so that there is no direct air access between the room and the drain pipe opening.

But, that said, if it's not a shower/floor drain that's used daily, the water in the moat evaporates pretty quickly anyway.

The purpose of a trap is to keep sewer gases from being able to easily escape from the drain pipe into the room.

My explanation might be a bit off, but I'm pretty confident the concept is correct.

Does your wife have long hair? I'm constantly removing hair from the drain cover after mine washes her hair.

Drain snakes available from Global House, but not cheap. Poor quality ones are available and cheap at hardware stores.

BTW, I don't have to worry about "sewer gases". Our pipe runs into the pond.