We have a single basin sink with garbage disposal. This has been backing up for 3 days and we've tried everything we know of, including: Clearing P-trap, Drano, snake/auger, and a pressure device on the hose. We've snaked from the sink, from the roof vent, from the basement. We've gotten only black sandy gunk and then some clear water, so we thought we may have at least partially cleared the blockage, but the sink is still backing up. Toilet, tub, and washing machine all work fine. We are stymied at this point and losing patience and fresh out of ideas. Is it time to call a professional or are we missing something?

Try to picture how your house is plumbed. If the toilet, tub and washerw rokits bgecause they tie to the main drain after your clog. Working upstream toward the sink your clog is apparently in a drain line dedicated to only the sink. Rodding isn't too difficult if you use the right equipment. Remove the trap and lateral pipe going intoi the wall, rod down this line with a 1/4" rotary rodder. You hit a 90 elbow about 6 inches into the wall and then it should be easy for about 20' or so, did you rod that far. Roof vent rodding is done with a power rodder on the roof, 1/2" minimum. Rod enough oreach roof top to basement floor plus 20 feet, I doubt if this is you area of clogging since the toilet works. I am curious about the black sandy gunk, try rinsing it to see what the sandy stuff really is and come back.

The kitchen is at the back of the house, and of course the pipe ultimately drains to the front of the house. Here's the layout as we believe it to be: Where the pipe enters the wall underneath the kitchen sink, it takes a 90 degree right turn, then (from here we're guessing somewhat, based upon our snaking experiences) the pipe travels about 2 or 3 feet, takes a turn downward for presumably 4-5 feet, then another 90 degree turn toward the front of the house. It's been difficult to snake around the bends, and the stack is somewhere in there also.

You are correct--the pipe from the kitchen is separate from the bathroom pipe, joins in a "Y" just outside the house and then travels to the street main. If the rodder you speak of is that pressurized snake-type device that travels through the pipes, we have not used this. The item I spoke of was an attachment to the garden hose that expands with water pressure to create a dam and supposedly forces water forward through the pipes--it does not, in itself, travel through the pipe. We have snaked from above and from the basement (daylight basement so pipes are above our heads), so we have a pretty good idea where the blockage is, just can't clear it. Next planned course of action is to cut out a section of pipe near the suspected clog for easier access and installing a fernco for any future (hope not) access. Do you think this is a bad idea? We are guessing the black gunk we've seen is a mixture of kitchen crud and perhaps rust or flakes coming from the pipes. Just smells musty. The only thing that has changed with our efforts thus far is that the sink will no longer drain at all, even after a prolonged period (like overnight).

We used a plug (I believe it actually is made for automotive applications) in the stack. Then, having a fair idea where the clog was, we used the garden hose with a pressure seal type attachment to flush the pipe from underneath the sink. After a few minutes without water backing up or leaking anywhere, we checked the cleanout at the property line and saw that the water was making its way there. It's been a long four days but it appears the clog is cleared now.