Hi, I'm Pete. I just joined the DIY Chatroom this morning. You'll find my intr
o in the Introduction Forum. I'm hoping I can be of some help to others, but for now I need some myself.
I own a house that I've been preparing for the rental market. It was need of some significant work. So far most of it is done, but I have a problem in the Kitchen which I would like to correct before renting it.
The Double sink does not drain properly. If I add fill up either sink and try to drain it the water will back up into the other sink and they both drain slowly.
I know this should not happen this way. My memory is a bit fuzzy on this part so please bear with me. Naturally I'm expecting some follow up questions, but here is the best information I can offer to get us started. I have had this problem addressed by professional plumbers at least three times when my father was still living in the house.
As I remember I was told that it had something to do with the venting or possibly how the the sink drain line connected to the main drain line.
The house is a track home (single story ranch on slab) built in Virginia Beach, Va in 1973. The plumbing is copper supply lines and (now) partly pvc to metal drain lines beneath the sinks, but originally they must have all been galvanized metal, including P-traps, per evidence under one bathroom sink.
The Main Drain line is cast iron. The Kitchen is on the back side of the house and the sinks are below a large chest high double window. Facing the sink the from the kitchen it drains from left to right. A garbage disposal (1 year old) is on the left sink. This dishwasher (right side) drains to the Garbage Disposal. The Right sink bowl drains directly into the drain and the P-trap is below it.
The drain line elbows from the P-trap and back into the wall from there. The old drain line from inside the outside wall has been cut and fitted to the pvc drain line, from the sinks, with a rubber pressure connector and hose clamps.
This was done a couple years ago by a plumbing company.
Further to right about 8' away the main drain line begins (or ends depending how you look at it) where it accepts the washing machine drain. The main is 3 or 4 inches and runs below and along the back edge of the concrete slab (draining right to left). Between the washing machine drain and the kitchen sinks drain is where the 1 1/2" or 2" vent pipe exits the roof above the eave.
Both bathrooms are at the left end (along the left side) of house where drain line curves and runs from the back to the front of the house picking up the two bathrooms. It exits from beneath the house near the left front corner and travels diagonally to the Right across the front yard to the city sewage connection at the street.
About a year ago after a backup I had the main drain scrapped all the way to the street and some roots were removed. I followed this up with a camera inspection and looked at the entire drain line from the washing machine drain back to the street.
It was clear and water was flowing as it should. The vent pipe located between the kitchen sinks and washing machine was also supposedly cleaned again at that time (although I personally don’t remember checking it). In spite of this the kitchen sink has remained a problem.
I'm replacing the dishwasher and the sink countertop so while I have them out of the way I thought it would be the very best time to address this issue and hopefully resolve it. I fully expect to cut the wall out to access the sink drain inside the wall. I know that the challenge will be replacing the rest of the sink drain and connecting to the old cast iron main drain. This will involve some digging to get to it beneath the slab.
The good news is that the back of the house is totally accessible (no bushes), so that shouldn't be a problem. All of this said, can I get some advice on how to proceed from there. I don't have much plumbing experience, dealing with large old fragile pipes.
Also, although I have no recollection of my parents ever complaining about drainage problems with the kitchen sinks while they were alive I'm wondering if it was just an issue they put up with. Could the placement of the vent pipe be the problem?
The following link should open a drawing
Hopefully, I've made this pretty clear and the experts out there can give me some needed advice.