- This topic has 3 replies, 3 voices, and was last updated 18 years, 1 month ago by nicktheplumber.
20 Mar 2003 at 12:20 pm #279211MasterPlumbersKeymaster
Can someone provide an educated guestimate for replacing a sewer line in the Washington,DC (Northern VA)area? The distance from house to street is 40′ and the depth is 4′. Single family home. Video inspection reveals current pipeline (cast iron) is in preety good shape–except for one portion where there are some root intrusions. Advised to replace total pipeline since there is a history of slow draining
and need for yearly snaking.
23 Mar 2003 at 9:08 am #300274nicktheplumber
One option that you should consider is the so-called “trenchless” sewer. This involves digging a hole at the far end of the sewer run and at the curb. You cut into the sewer at both ends and snake (with a powerful hydraulic puller) a polyethelene pipe from one end to the other and tie it all in. You may have to dig one or two ther holes along the way to make lateral connections to other house drains. This is a lot easier than digging out a long trench and laying CI pipe all the way. An advantage to PE pipe is that it is seamless and quite immune to subsequent root incursions.
The only caveat is that the PE pipe (which is pilled through the existing clay or CI sewer line) ought to follow a proper slope. If the existing line has a dip in it, the trenchless line will not correct the problem.
Trenchless sewering requires special (expensive) equipment.
25 Mar 2003 at 10:47 pm #300275Delmar
When you refer to “dip”–I assume you are speaking of a situation other than the natural slope of the line caused by movement of the pipe from its original placement(?). No doubt that the equipment for trechless line replacement is expensive—but does that translate into being more expensive to the customer as well? It is my understanding because there is less manual labor involved–the cost is 1/2 you would expect from a
conventional replacement job. Is this the reason “tenchless plumbers” are hard to locate in the Washington DC area?
26 Mar 2003 at 4:10 am #300276nicktheplumber
By “dip” I mean a sag in the drainpipe below its normal (designed) frainage slope. This happens when a run of drainpipe sags in the middle of a run. You can see that in crawspaces and basements with poorly supported pipe runs. You also can find it in buried runs of soil pipe, for example where a “sink spot” develops under the buried run.
Such buried sags cannot be corrected by trenchless sewering, since the new pipe is simply pulled through the buried pipe, and the PE pipe is somewhat flexible (i.e. it will follow the sag).
That being said, if the pipe slope is good, trenchless sewering can be a less expensive way to replace a long run of buried sewer line. The main costs of sewer replacement are: 1) labor; and 2) materials. On both counts, trenching out an old line and replacing it with hubless CIP and fittings is more expensive than doing a trenchless job with PE pipe, unless you have a really short run to replace.
I stopped doing major residential sewer line replumbs several years ago because of the time and labor (backbreaking) involved, and the fact that we have several trenchless sewer tapping outfits here.
I can’t say anything about your local costs, but in the SF Bay Area, replacing a 60′ run of sewer line would run the homeowner about $10-12K by “conventional” means, and $6-7K trenchless. So figure on a 30-40% savings…
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