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Question DetailsAsked on 3/3/2018

How do I clear a rock in the main line that is only about five feet from the city sewer line?

We had a plumber out three times in less than three weeks for main line clogs before discovering a rock in the main line about five feet short of the city sewer line. He proposed two options, first I think he meant jetting for $800+ or digging up the line and sidewalk to get to it. I thought of just pushing a garden hose down the line and pushing or washing out the rock with or without assistance of a gas powered pressure washer. Any guidance?

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I wish you had said HOW you know there is a rock - was a camera run, or did he just "feel" it - which might mean instead of a rock a broken pipe or offset joint maybe.

Unless you were pooping the proverbial rocks because of the SuperBowl, or you have an open cleanout standpipe which a kid could have dropped a rock into, the rock had to come from somewhere outside the pipe - meaning you almost certainly have a broken line. And if it is dropping in large enough or enough rocks to cause 3 clogs in 3 weeks, it really should be fixed ASAP.

Normally, I would recommend cleaning the line - at least to the rock, then running a sewer camera (some jetting tools have them mounted on the nose so two birds with one stone there) to see not only where in the line the rock is exactly (using a radio locator head on the camera) but also if it came from that spot or maybe a hole in the pipe further upstream and got partly pushed down the line by a moving clog with a backup behind it. I have seen several cases, including ones through sidewalks or in the street, where the actual line break was upstream and could have been easily reached by digging in the lawn and then pushing the rock out from that opening.

Anyway, having an exact locate on the rock and any pipe break would be VERY useful if it comes to digging up the line to repair it.

I really doubt a garden hose will do the job unless only a few feet from an upstream cleanout - not enough water force (and hooking a pressure washer to a hose is a BAD idea - besides, that is basically what a jetting tool is) and the hose is not stiff enough to push any substantial sized rock through the line. PVC pipe glued tgether in lengths in an excavated pit can commonly do it if the rock is not close to or larger than pipe diameter. A jetting tool or cable router for typically $200-300 range can also commonly do it if the rock is smaller than the pipe (talking 3-4" residential sewer pipe here), as can a vacuum truck (which is usually more expensive).

But without a camera run showing the cleaning tool is not going to jam in the pipe, or that it is actually a pile of smaller rocks which can be washed through, AND that they are not being held there by some roots (which might be the pipe break cause in the first place), I would not count on this working. Also, many cable router operators will not run a router or jetter into that situation without visual proof it is not going to roll in the pipe and jam their tool with it. Also, if a broken pipe, there is a chance of trapping the tool in the pipe with further rocks and dirt falling into the pipe once you remove the existing rock or pile of rocks.

But - even if you get the rock out, unless the camera shows no pipe damage (so the rock was dropped into the pipe), you still presumably have a broken pipe to repair - which I would presume was the $800 number. Without that, you will periodically be getting rocks and dirt dropping down into the line and clogging it, eventually can open up to a sinkhole in your yard - or in this case maybe under the sidewalk or street, which could get expensive because you would normally be held liable for the repairs.

Also - ask plumber or sewer cleaning contractor or call the utility on what the city/utility rules are on pushing rocks into their line - some will, if tht is the situation, come with a vacuum truck and vacuum the rocks out of your line to prevent them from going into the sewer main, especially if a small diameter main or if there is a lift pump downstream, which the rocks could cause damage.

So - my recommendation - camera run to locate the damaged point(s) and rock location, which would also tell you if your line is actually so deteriorated tht the whole thing should be replaced, getting utility to vacuum it out if they will/can otherwise maybe jetting or routing the blockage out if able to do so (not to big to wash/push through pipe to main sewer line) if the actual repair cannot be done immediately, then repairing the line by excavating it.

There is the option of lining the pipe with an epoxy resin and fabric liner (sort of like fiberglassing the inside of it) but I am not a fan of that for small lines like this because it reduces the diameter of the line, and unless run all the way up into the house to where the lines are smaller, gives you a smaller line diameter downstream than upstream - never a good idea. And unless you are in a case where excavating is difficult or expensive because the excavation would be under a building, under a street, under a favorite planter or tree, etc - it is usually cheaper to excavate up to a hundred feet or so than reline.

Answered 2 years ago by LCD

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