Hi, I am living in a ground floor condo and sometimes water is coming up through my sink. 

 

This seems to be a common problem with ground floor condos. One neighbour suggested to build in a valve, but this would mean I need to open and close it every time.

 

Does anybody have any other suggestion?

 

You need an in line non return valve, but make sure the arrow faces to out side 

It will let the water out but not come back up the sink & nit doesn't require turning on / off

 

 

The reason why you get flowback is because the pipe is either partially blocked or the pipe diameter isn't big enough to take the waste water enblock. You need to get the pipe cleaned out or replaced after the junction where your pipe connects. Thais know naff all about pipework IMO.

22 minutes ago, Rally123 said:

The reason why you get flowback is because the pipe is either partially blocked or the pipe diameter isn't big enough to take the waste water enblock. You need to get the pipe cleaned out or replaced after the junction where your pipe connects. Thais know naff all about pipework IMO.

Yes I would be looking into this as you only mentioned the sink

Because in reality if there was a problem in the main line due to small blockage & all units using the system it would back flow up the lowest drain, which would be on the floor 

The reason why you get flowback is because the pipe is either partially blocked or the pipe diameter isn't big enough to take the waste water enblock. You need to get the pipe cleaned out or replaced after the junction where your pipe connects. Thais know naff all about pipework IMO.

Indeed.

The OP should probably be thankful that it isnt the toilet drain that is blocked as he would be the first in the building to know about that also. There are advantages in living on high floors.

The normal one way non return valves available here would be unlikely to work in the situation the OP describes. Most of the valves I have seen work on a seal that is held in place via a spring. You will not get enough pressure on a draining sink on the ground floor to overcome the spring force.

Better to try and find out what the real problem is and sort that out first.

8 minutes ago, Formaleins said:

The normal one way non return valves available here would be unlikely to work in the situation the OP describes. Most of the valves I have seen work on a seal that is held in place via a spring. You will not get enough pressure on a draining sink on the ground floor to overcome the spring force.

Better to try and find out what the real problem is and sort that out first.

Fair call

You should contact the condo manager and the maintenance employee .Before you all write what a waste of time this will be it will probably not be the first time the ground floor units have had this problem .If the underground pipes need re plumbing in the common area your maintenance fees  should cover the cost .That's why you pay the fees to correct issues such as yours .

Thanks a lot Bevup, your tip was fantastic. By the way, in Thai it is called check valve same as in English.

First pour a bucket of very hot water down the sink.

Then I would get a packet "green" of enzyme based grease remover. 50 baht (HomePro, BigC, Tesco, even some local mom and pop hardware store). 

 

 

Obviously somewhere down stream the waste ware pipe is partially blocked. Thai/Asias are famous for pouring grease down the drains where is coagulates.

 

Pour said powder down the sink and wait. 

 

I do not recommend putting a check valve in the sink discharge. It will just get clogged up.

 U1)  caustic soda,30 baht. OR try this : 2)  baking soda into drain then Distilled white vinegar, 150 baht. 3) Mister Muscle drain cleaner, 150 baht. 4) Straight bleach, 100 baht. These remedies can go separately or one after another. DO NOT MIX BLEACH WITH AMMONIA, this makes a deadly poisonous gas. Yes, I live on a ground floor house. All these items can be found at TOPS supermarket for under 500 baht. My problem was my toilet. Use into a full sink or toilet. It make take a while, but if takes time use more chemicals. These all will cause bubbling. Be patient, let the chemicals do the work. Flushing the toilet with chemicals in it will not help the problem, let the chemicals SLOWLY do the work. USE RUBBER GLVES.

Edited April 27, 20188 yr by themerg

If water comes up even when you don’t use water, the main line for sink is the problem. 

Edited April 27, 20188 yr by The Theory

1 hour ago, themerg said:

 U1)  caustic soda,30 baht. OR try this : 2)  baking soda into drain then Distilled white vinegar, 150 baht. 3) Mister Muscle drain cleaner, 150 baht. 4) Straight bleach, 100 baht. These remedies can go separately or one after another. DO NOT MIX BLEACH WITH AMMONIA, this makes a deadly poisonous gas. Yes, I live on a ground floor house. All these items can be found at TOPS supermarket for under 500 baht. My problem was my toilet. Use into a full sink or toilet. It make take a while, but if takes time use more chemicals. These all will cause bubbling. Be patient, let the chemicals do the work. Flushing the toilet with chemicals in it will not help the problem, let the chemicals SLOWLY do the work. USE RUBBER GLVES.

1) Caustic soda is really nasty stuff.
3) in the past, some of the commercial stuff I used destroyed a drain pipe from a long gone era. (as would Caustic Soda I think.) and I thought I solved the blocking. Until I found out with some help of the neighbors downstairs that I didn't.
4) bleach can help obviously, but nasty stuff as well.
2) I used my self many times, poor as much hot water in the drain pipe as possible to stimulate the chemicals solve the blockage. 
Note: some of the quality beautiful shining plugs severely discolor, better to take the cover out.

Edited April 27, 20188 yr by KKr

7 hours ago, themerg said:

 U1)  caustic soda,30 baht. OR try this : 2)  baking soda into drain then Distilled white vinegar, 150 baht. 3) Mister Muscle drain cleaner, 150 baht. 4) Straight bleach, 100 baht. These remedies can go separately or one after another. DO NOT MIX BLEACH WITH AMMONIA, this makes a deadly poisonous gas. Yes, I live on a ground floor house. All these items can be found at TOPS supermarket for under 500 baht. My problem was my toilet. Use into a full sink or toilet. It make take a while, but if takes time use more chemicals. These all will cause bubbling. Be patient, let the chemicals do the work. Flushing the toilet with chemicals in it will not help the problem, let the chemicals SLOWLY do the work. USE RUBBER GLVES.

Perhaps you would be kind enough to post the chemical reaction which gives a deadly poisonous gas. Wearing my hat of a qualified analytical chemist, the only reaction I can perceive relates to exotherm created by mixing concentrated ammonia with concentrated sodium hypochlorite, in which case ( depending on stoichiometry ) either ammonia gas or chlorine gas is evolved. Under more dilute conditions, the result would be innocuous ammonium chloride.

On 4/27/2018 at 8:40 PM, Lacessit said:

Perhaps you would be kind enough to post the chemical reaction which gives a deadly poisonous gas. Wearing my hat of a qualified analytical chemist, the only reaction I can perceive relates to exotherm created by mixing concentrated ammonia with concentrated sodium hypochlorite, in which case ( depending on stoichiometry ) either ammonia gas or chlorine gas is evolved. Under more dilute conditions, the result would be innocuous ammonium chloride.

Here you go...

https://www.thoughtco.com/bleach-and-ammonia-chemical-reaction-609280

Edited May 5, 20188 yr by judokrab