Main sewer line replacement..

27 Replies

Im sure tons of you have replaced your sewer line yourself.. hopefully.. lol
bout to tackle this project myself and hopefully save several thousand dollars.. just wondering if anyone had any advise they'd like to share..
property was build in approx. 1930's and I doubt any repiping has been done, line has collapsed and needs completely replacing according to the several plumbers ive recieved bid on.

Just looking for advise.. doesnt seem too hard to me, plan is to rent a mini excavator, dig up yard (120 feet back yard house to alley) then lay new sched 40 PVC down..
couple questions..
can i just lay the new pipe over the old clay pipe or do i need to remove the clay pipe?

I see the digging being the worst part.. dont see laying the pipe and tieing it in being a big deal.. plan to put several clean outs, on both ends.. any advise anyone!? I'd greatly appriciate it!
p.s. plan on doing 3" pipe.. small house has 1 bathroom..

Scott, this is only an opinion because I have not replaced an existing pipe, but for the new pipe that I had to have done, there were some specific requirements that had to be met in order to tie in to the water companies pipe.

Therefore, I would ask most of these questions directly to the water company involved to see if there are any specific things they will look for before they allow the water into your pipeline.

I would not lay the new pipe over any existing pipe because of the possiblity of water pressure vibrations could accidentally vibrate the new pipe against some sharp part of the detoriating old pipe causing a eventual break in the new pipe.

Hi Scott, Go for it. Stay away from the alley. I doubt there is a city in the USA that will let an unlicensed plumber touch it. Take out the old pipe and put the new 3" pipe in it's place. When you get to the alley, pound the 3" pipe into the 4" clay pipe to get as close to or into the main line. Cut the front at a 45 degree angle and bevel the edges. Mark the pipe every 12 inches so you know how far in you are. Use a wood block to protect the pipe. Seal the connection as you normaly would with a rubber 4" clay to 3" pipe reducer coupling.

Sometime that pipe can get deep - especially toward the end depending on how it was installed.

I do not know the exact rules because I secure all trenches but - and this also depends on the soil - the looser the soil the more shallow you need "shoring" If it's more than a 3-4' deep take care and slope the sides- the deeper you get you need to secure the sides. if you do not - you will die .

Sorry to be so severe but it is so easy to die in a trench it is not funny in any way. Usually sewer line do not get too deep until the end - but you never know who installed it - hence my post in this thread.

Depending on your soil - make certain your mini-excavator is big enough for the job - nothing worse than having a machine too small and fighting it rather than spending the extra $50 to get a bigger machine. I used a mini-excavator one time in solid almost rock soil and it was a waste of money.

Anyhow - I was primarily concerned that sometimes pipes get deep especially over a 120' run - if yours does then do not get into that trench - no one realize how easy it is to die in a trench - even if just above the waist - Yes, just above the waist.

I've not done this but I have paid to have it done. I've also used backhoes and skid loaders. There's some technique, so plan on a bit of a learning curve if you've not done it.

When I paid to have it done, they dug out the old line. Frankly, its hard not to dig it out, since it breaks up as soon as you hit it with the hoe.

These guys dug down maybe six inches below the old line and put down a gravel bed. "Squeege" its called around here, similar to pea gravel. The leveled this out, the laid the line on it, then embedded the line in the gravel, too.

I can't really imagine this as a one man, DIY job. This was a whole crew, maybe six guys. One was clearly the supervisor, and he's the only one who drove the hoe. The others did everything else. Mine was about 90' and it was an all day job. Working alone I'd allocate several days to this. You'll need to rent the hoe the entire time.

Not sure what you mean by "mini". My line was maybe six feet at the deepest. They used a small hoe, but it was quite a bit larger than some of the mini ones I've seen around. Be sure you know how deep you need to go and get a hoe that will go at least 1' further.

As others have said. ABSOLUTELY do not get in that trench without shoring. You should be able to rent the shoring device. The ones they used were two plates with hydraulic cylinders between them. They used a hand pump to work the cylinders. They had a couple and they moved these around as needed.

I'd hire someone who really knows what he is doing to do the digging. If you damage the city's sewer it's not going to be a good thing and it's not hard to do with a backhoe.

Call and have all utilities marked, even if you think they are nowhere near where you are digging.

Be very careful about sanitation. You can get sick by handling sewer line. Disposible gloves, keep your hands away from your face, etc.

For sure dont dig 'too' deep and throw in some loose dirt to make your pipe level. It WILL compact and settle a low spot in your pipe. Better to dig last part with a spade and use Jons idea of bedding in gravel. gravel does NOT settle. and only on top of undisturbed soil,,,it its loose throw it out of the trench. Find out how deep your outlet end is,,might be surprising,,and might require equipment you cant rent.(easily).

Bettter check and see if your sewer CAN be 3". I like 3" better than 4 because it dishes more and carrys solids better with less water BUT not everyone has same opinion,,,namely inspectors that have to approve the install.

And get that utility locate. Snagging a gas line,,or even a phone line can ruin a nice day in a hurry.(try a 50 pair fiber optics cable,,,or bigger)(and see how big of bill they send)

Hi, I had a 2 rock bungalows built in the 30s. Both lines were replaced. I had to have a plumber by ordinance for this. But, I supervised, LOL! Take the clay pipe out and use roofing felt on the bottom, then a gravel base, trench it deeper and build it up to the slope we used rocks to brace it. cover with gravel along the sides. Don't put rocks on top of the line as you back fill, if you ever drive over it you can push a rock into your line, car can cause that a foot and half below grade and a large dump truck can push 3 feet down (a rule of thumb around here, but that depends on soil type, rock, etc), but consider that since you are near an alley. Sounded like , Sounds like Christian had some good tips to tie in. When you call the gravel pit for delivery, they can tell you what size to use in your area. It's really a chitty job, but one man and a boy (or a supervisor) can do it just fine. If you get very deep take care with the sides as mentioned, but in CA. you could fall into a fault line and die too! Good Luck, Bill

So far so good.. really wasnt that bad.. started off day around 10am, dug a hole to check where the pipe was for sure, got all the materials i needed (PVC), got sand delievered, bobcat mini excavator showed up around 4 and started digging.. didnt dig the front 10' close to the house, started digging bout 10' from house, proablly got 60' done.. maybe another 30' to fence (deepest part) bobcat took a bit to get used to but then it was pretty simple after that.. Discovered the pipes are the old clay pipes, and its burried right below the gas and water lines.. eh..!
Ended up digging right next to the line, going to leave that line there and replace it with the new one right next to it.
Tenants are in hotel, so trying to get this done asap! took about 4 hours to get where ive gotten, need to dig some of it by hand, but seems to be going good sofar! hopefully another 2 hours on the bobcat and most of the trench will be dug.. then ill dig the rest out by hand, throw some sand in there and lay some pipe! now since im moving the pipe over about a foot, im thinking just two 45 degree connectors on each side should do the trick!?
thanks for all the replys!

Christian- thanks for the quick and awesome reply, had something like that in mind, but just didnt know if it'd actually work! :) well were gonna find out! thanks again!

Steve- Lining was not an option, as the pipe had collapsed in several different spots trench wasnt a big concern to me anyways, back yard is not landscaped otherwise I would be looking into trenchless or relining!

Don- 3" is allowed, I was going to go with 4" but everyone says 3" will be just fine if not better.. so 3 it is!

Im probablly at about three and a half feet, still got prob 30 geet to go.. id say four and a half total is my guess.. id say it doesnt meet the drop requirement.. which is like 1/2 inch for every foot or something i heard.. it doesnt seem to slope much at all!
The top foot was just mud, theres actually still snow on the ground, and the soil is very wet and easy to dig, even when i dug by hand..bout 2 feet down theres like clay or some harder dirt that is a pain to get through.. plus even the mud was freezing come around 8 tonight.. by 9:30 when i left i was walking on top of the mud tracks the bobcat made, without getting muddy! lol
plan is to go out in the morning around 8 and start, but still suppost to be like 22 degrees and with wind chill will feel like 14 so might not.. but bobcat goes back tomorrow!

Wow.. that was a nighmare.. ended up not good at all.. calling plumbers in morning as i just got home and its 11:20.. hit the water line, busted of course, then then i hopped down into the hole i put my hand on the gas line and into my hand it came,.. bad idea i guess but it must of been very loose to begin with.. Sewer is NOT a DIY in my opnion, doesnt seem hard, especially when digging with a backhoe or excavator, but that alone is exhausting, im beat and didnt acomplish much today, hole is probablly mostly dug.. guess we will see what plumber says tomorrow.. eh..

having your lines marked is probablly the number one and most common thing to do, pretty well known, but the reason I didnt is when I called the dig alert people (its 1800digalert in arizona, something different in texas forgot what i called) they said they wouldnt mark it for around 5 days due to the ground having snow on it, and 5 days wasnt an option at that point, couldnt of been prevented real well anyways as they were on top of the sewer. $4000 later were gonna be legal.. problem is new law effective oct 09 in texas states something among the lines of if you upgrade the water lines, everything effected by the water lines has to be brought up to code something like that, so water heater needs couple new vents, pan, gas line doesnt have a riser on the outside of the house it comes up underneath, all costly additions to the orignal plumbers estimate, and were not done yet. worst part is the excavating I spent days on and good money isnt gonna be good enough as now were replacing all 3 and they have to be further apart then they orignally were.. bummer.. what a waste.. exciting adventure.. learned never try that again, plumbers charge a premium and theres reasons why.

Updated over 9 years ago

regarding that new law i mentioned im not sure if its texas wide or a local town/county law..

In my experience the required locate service is only looking for public lines, not private lines. I've done excavation several times, and always called. With the exception of gas, they only marked the street, not onto my property. The gas company marked up to the meter, which is right next to the house. So, I don't think this would have helped up.

Sorry your experience with the digging worked out badly. Thanks for sharing, though, there's a good lesson there.

$4000 doesn't sound like a bad price for the work, though. I paid that for about 90' of sewer line, though that doesn't include the last 10' under the street. That would have been another $6000. A friend paid about $8000 to replace hers.

Yea even if it was marked it wouldnt of helped, i knew where the pipe was, i followed it all 90 feet before i hit it! lol I just didnt mean to hit it obviously but did... whops..
the $4000 seemed reasonable to me as well, its like 120' to the middle of the alley, luckly its in the alley and not the street, alot cheaper to dig up! (dirt)
The city says the main sewer is roughly 5' deep, its a corner house, unsure if this is correct or not.. that did include tapping into city main which is the big cost item. Also included bringing everything up to code, lots of little things.. sucks but its waranteed for 10 years now :)

I have to admit I cracked up when I read your post yesterday. I've done more than my share of digging, and totally sympathize with what you must have felt with you hit the water line. I still have bunged up places in my siding from digging window wells with a backhoe. Just seems like they have a mind of their own sometimes.

I dont know if this will help you or not in your situation but I will throw it out there.
They have a product that is a new pipe relining system that will line the old cast iron sewer pipe lateral with a new, continuous pipe made out of resin to protect against future tree root infiltration. I have scene it done one time on a job. To me the best part about it is you dont have to dig up the entire yard, only where the connection is made to the city line.

Ive heard and seen a few articles and watched this old house where they relined the pipe, unsure if i like it or not, kind of too new for much information, mine was actually collapsed in a place or two and this wasnt an option, didnt even really look into it. They also have the trenchless replacement where they pull the new pipe through, thing is the backyard is not landscaped and i wasnt worried about the trench. The digging by the city hook up is what cost about 50% of the total people pay to replace the line, its either under the street (VERY COSTLY) or in the alley as in my case, but atleast here the city is very strict on digging in the alley, the contractors have to have TONS of insurance for that job, they have to warrantee it for like 1 year that it wont sink and bring more dirt out if it does, grade it and such, pretty big job for the contractor doing the digging in the alley and this is why they charge so much. I understand, just sucks. Just a comparison they said if they wernt connecting to the city main, which if your going to do the sewer you really need to, but if they were to stop at the fence (10' from main) the price to replace the sewer would be about half. plus thats the deepest part they have to dig, in my case only around 5-6 feet to city main and just my luck, my side of the alley is where all the water/gas/phone/cable lines are ran, if i was on the other side of the alley it'd be several hundred dollars cheaper, because around these areas they say they're gonna have to hand dig.

I worked for an electrical outfit for a bit and was on a digging crew. My foreman used back-hoes everyday for years and he still always managed to break at least one line every time we dug a ditch. Hand digging sux!

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