Home & Garden Columns

About the House: House Sewer Piping with Trenchless Technology

By Matt Cantor
Friday September 15, 2006

I am not a high tech guy. Ask anyone who knows me. I like technology. I respect modern whiz-bang innovation but, personally, I’m very slow to adopt anything newer than about 1965. In many ways I’m slower to adopt anything newer than the 18th century. I was listening to Linda Ronstadt interviewed on the radio the other day and she said that she really liked 19th century songs and that after about 1910 they just lose her. I’m like that. One reason is that Old is time tested; crushed, run over and aged some more. If it still works, well then you’ve got something. So when I say that there is a new technology that’s worth looking at (here it comes) I do it with some impunity. So here’s what’s new. Ready. Sewer pipes. Bet I surprised you. 

Sewers in our old housing stock are about as advanced as the Swiss Family Robinson treehouse. No moving parts and almost nothing you couldn’t make with a bunch of Hittites and a mud oven.  

The sewer pipes that run from our houses out to the street have largely been made, during the last century of clay, simple terra cotta. In fact they look just like the tiles on our roofs except that they’re tubular rather than hemi-cylindrical. These pipes, buried between the house and street are usually fitted “bell and spigot” lengths, packed at the joints with mortar. 

Bell and spigot fittings are ones where one end swells to be able to accept the insertion of the small end of another. This is what most cast-iron piping has looked like over the last century as well, although cast-iron bell and spigot was packed with a fibrous material called oakum as a backing and then filled with molten lead (leading to the slow death of many a plumber. Thank goodness we stopped doing that). 

The part of your waste water system that we’re talking about here is distinct from the DWV (Drain, Waste and Vent) piping inside your house (including the basement or crawlspace). It’s the part that’s outside the house and runs from the house (usually along the side) out to the street. The rules for these have long differed from the inside part and it is here that we experience the most serious problems. Some of these come from the primitive manner of construction but there are an attendant array of nasty failings that can descend upon thy pipes as well. They include root intrusion, breakage and dislocation as well as the usual blockages. 

Plants like to be watered and roots follow the water just as surely as Woodward and Bernstein follow the money. Roots have a wonderful methodology for destroying clay pipe. They enter at cracks or loose joints as tiny tendrils looking for a drink (lots of nutrients there too) and slowly grow bigger and bigger, thus cracking and splitting the pipes. 

They can also fill the interior of a pipe so densely that the flow of solids becomes nearly impossible. For nearly a hundred years, we’ve been using metal “snakes” with bladed heads to help cut these out but the roots keep coming back. 

Cracks in the piping can come from soil movement or pressure applied to piping near the surface. A truck backing up over your driveway can do this so try to keep the big trucks off your property. Locally, we have quite a bit of soils migration and hillside creep (not me). 

Both of these things can crack, dislocate and separate old clay (as well as newer cast iron) pipes. Therefore, I give special attention to these “sewer laterals” when looking at steep lots, wet lots or ones that show other evidence of soils movement or settlement. If the foundation is cracked and settled, I assume, generally, that the shallowly buried sewer can’t be very different, especially if it’s clay. 

Now, other materials have been used in the last 50 years or so (although clay is still used to some degree to my head-shaking amazement) and these others are far preferable but the failings I’ve noted can still occur, especially when soils movement is prevalent. 

The difficulty with this array of possible defects is that they’re so hard to diagnose, or, at least, have been for most of my life as a result of the inaccessibility of the buried pipe. In the past, we could only respond to clogs or obvious leaks (Eeeeeeewww) by calling someone to either snake out the pipe or dig it up. This might mean the replacement of a concrete pathway, sidewalk or driveway. 

A backhoe might be digging a swath through the narcissus and overall, these repairs were ungainly, expensive and destructive, but Technology is here to save the day (and a whole lotta money). We’re really lucky because we have two technologies here and they work together beautifully. The first is diagnostic and the second is surgical.  

There is no way that one can avoid comparing a sewer video camera with a colonoscopy (for o’ so many reasons) but that’s basically what it is. The system has, just as in the O.R., a camera mounted on the end of a long snake-like semi-rigid cable and a TV at the other end. There are also some cool features with some of these like the ability to “right” the image, since they tend to put you upside down as you’re watching. A flush of the toilet cleans the lens (Eeeeewwww) and you can then see all the cracks, bellies (where the water sits) and offsets (where the pipes don’t meet straight in line). 

You can also easily see the roots and other clogs prior to taking any action. Information is power and this thing leaves you without any question, so it is a very powerful tool. 

Most operators will give you a video copy of the inspection as a part of the inspection and you can expect to pay anywhere from $50-$250 for the service. But if you consider the cost of digging up a pipe, just to examine it, it’s an incredible bargain. The devices also come with a locator system that allows a break in a pipe to be pinpointed with great accuracy (depth too). 

Be sure to pop that video in at your next dinner party just before the appetizers (Eeeeewwww). 

The surgical technology that marries with the previous one so nicely is also nothing less than astounding and I mean that in a very fundamental sense since it changes the way we not only look at these system but removes a great body of distress that was formerly common to any work on these systems. 

It is a system that replaces buried pipe without trenching. Holes do need to be made where the pipe replacement begins and ends but no other digging is usually needed (though sometimes, thing don’t work out so well, right). 

A cable is run through the old broken piping from one hole to the other and a powerful winch is set down inside one hole. A heat-fused, continuous length of polyethylene piping is then pulled from one end to the other. 

It is not pulled through the piping, rather it replaces the former by “bursting” or splitting the old pipe out of the way, as the new one is pulled along. A bullet-shaped device with a cutting fin is pulled by the cable and the new pipe is fused to the back end. 

This means that a 4” pipe can be replaced with a 4” pipe and since the new pipe has no tiny breaks, roots can’t start to grow at all. Furthermore the very thing we hate about plastic, the fact that it doesn’t biodegrade, is precisely what we can love about it in this situation. This is what plastics are good for. Lastly, the piping is flexible and can stretch and bend as the earth moves and in my never humble opinion, I would guess that these laterals will outlast almost all the houses they’re installed at.  

This technology makes the work so much faster and easier than the old trenched jobs that the cost of a replacement has dropped by at least 100 percent since they’ve come along. If you were formerly looking at replacing a driveway to repair the sewer, you could be saving 300-500 percent. 

In real dollars I used to see (this is 1980’s dollars) $5,000-$15,000 on lots of these jobs and now we’re usually looking at $1,000-$4,000, so it’s time to stop paying the rooter guy to come every six month for ever (say it like a teenaged girl. I am soooo sure). 

Now here’s the part you need to pay attention to and I apologize for putting it at the end but I felt it was important to lay the groundwork, as it were, in advance. 

If you live in many of our east bay cities and you’re getting ready to sell your house, you’re going to need to have an inspection of your system done. In Alameda, you’ll have to do a wet test in which your entire system (up to the top of the foundation) is filled with water and shows almost no leakage in a 15 minute period. This may involve putting in a special fitting at the sidewalk which can be blocked by a plug. 

If you’re in Albany, Richmond, El Cerrito, Kensington and parts of West CoCo County you’ll need to complete a video camera inspection prior to transfer of the property. Almost any sign of failure in this examination will require a repair of the affected area. If your lateral is clay, you’ll almost certainly be required to replace all of it (and good riddance, I say). 

As of Oct. 1, Berkeley joins this club, so those of you now looking to buy or sell here should be prepared to get the test and negotiate the results. I believe Oakland will follow suit in the near future and eventually, I’d guess that this will come to all sewer districts. 

I’d like to thank my buddy Paul at Central Plumbing and Rooter in Alameda for taking time away from the kiddies to answer so many of my questions. 

Nobody likes to go to the doctor but we all go because we’re rather face the news sooner and have the time to take action. Now, take a deep breath. This won’t hurt a bit.