Unblocking a sewer pipe

[Balthasar G.]

Right after the first rains that Sonca brought with it our septictanks filled up very quickly. We couldn’t use our toilets any more and called the septictank service. However, after the next downpour we had to call them again because the tank had filled up again. After yesterday’s shower the same happened.

Next to the septictank proper there’s a small drain in which the gray water is collected. The excess water of the septictank also overspills into this drain. This drain is connected to the street sewage system. However, the water doesn’t flow away so it would seem that the pipe that runs from the s eptic tank’s overspill drain and the street is blocked. The distance from this tank to the street is about 15 meter.

Can anyone recommend a service that could unblock this pipe? We live near Big C.

[SJP17]

Could you not run drain rods down it or is it difficult to access ?

Failing that you'd probably need to jet the drain with a pressure washer with the jetting head I am not really sure who does it I asked the wife and she said contact government office.

[mickojak]

There's something wrong with your setup.
The rain should not affect your septic tank as it should only fill from your toilet.
You need to find out how the rain water is getting in,
but it sounds like it's coming in through that pipe to the street.

Have a closer look.
Something not right??????
Mick

[Balthasar G.]

No, I'm sure there's nothing wrong with the set up itself. We've lived in this house for almost 10 years now. Never had any problems with this tank. With the other one we did. It filled up after heavy rains and we couldn't use it. The reason is that that one doesn't have a connection to the street with the municipal sewer system.

This one with the connection to the street, however, has always worked fine. I'm using a small pump now to empty the overspill tank and you can see the water from the sewer pipe running back into the drain. So it's highly likely that the pipe to the street is blocked.

[mickojak]

Ok, bit why does it fill when it rains.
None of that water should get into it?
Mick

[Balthasar G.]

It's not an uncommon setup in Thailand.

[Balthasar G.]

Could you not run drain rods down it or is it difficult to access ?

Failing that you'd probably need to jet the drain with a pressure washer with the jetting head I am not really sure who does it I asked the wife and she said contact government office.

I've never seen drain rods here in Thailand, besides the drain is quite long (abt. 15 meters).
I do have a pressure washer and have already established that a sewer hose will set me back a few thousand bahts. I prefer not to spend that much money on a hose that I will probably never use again, and also because I'm scared that (a section of ) the drain might have been damaged/invaded by plant roots and will then need to be replaced anyway.
I hope that your wife's tip about the government office is feasible. We'll contact the puyai bahn tomorrow.