Washing machine waste pipe leaking after kitchen sink cleared!

PalerPaul

Hi,

I'm hoping someone can help me here. I've been having some problems with the drains in my kitchen and while I've sorted some of it out, I'm still having some problems.

It started when the kitchen sink was draining very slowly (like 5 minutes to drain the entire basin). I left it for a day or two as it came on very quickly and I hadn't had any draining problems up to then. It didn't progreesively become slow.

On doing a water change for my fish tank, I poured a bucket of water down the sink and some of it came back up the pipe the washing machine drainage pipe goes into behind the washing machine. It was about 3 or 5 mug fulls and not the entire bucket.

I got some caustic soda and gave the sink two treatments and poured some of the misture down the pipe the washing machine waste pipe goes into. Eventually, this cleared the sink up completely and it drained fine from then on.

However, when I put the washing machine on, at the very end it is bubbling up about 2 mugs of water back up. It seems to bubble and spit rather than just pour out. I have made sure that the washing machine waste pipe is about 7 inches into the pipe and there is plenty of space around it for air. The kitchen sink still works fine and I've checked the u bend on the sink. When the washing machine is draining, it doesn't spit at the time when the water is being pumped in full flow out of the machine but at the end when it is draining much slower. This leads me to believe it isn't an ordinary blockage.

I live in a top floor apartment of a mid 80s build. Because of the build (and my knowledge of plumbing!!!), I can't easily see how the pipes interact. The one that comes down from the sink goes into the concrete floor and the pipe that the washing machine drainage pipe goes into is beside it, rising from the concrete. I imagine that both of these go into a bigger pipe just under the concrete. In the hallway of the floor of apartments (2 on each floor), I have access to the press that has the main pipes and I can hear water running into it. My toilet and bathroom aren't effected at all.

What is frustrating is that I can't use a plunger on the sink, becuase when I do this, the vacuum fires water back out the pipe the washing machine waste pipe goes into. Last night the sink became blocked completely for about a minute but then it was fine. If I drain any amount of water down the sink, it will making a gurgling sound (often a couple of seconds apart).

I'm not sure if this is as simple as a blockage or if it is air trapped (if that can actually happen). I don't want to get a drain cleaning firm out or a plumber until I have an idea which one would be able to fix it.

Does anyone have any idea what could be causing this or had this happen to them? Any help greatly received!!!! Sorry for long description but thought it would help identify the problem.

PeteHeat

Hi,

It may be a small blockage in the pipe in the floor, it's open enough to allow small steady flows of water but can't take a full flush through so it backs up the nearest outlet at the washing machine.

Another possibility is there is not enough air being released at the soil stack, you may need an air admittance valve fitted to balance the pressure.

Take care with caustic soda and pvc it tends to etch the inside of the pipes causing more blockages.

.