Three Environmental Factors that Cause Service Lines to Fail

By: Bill Eller September 26, 2018

Are your residents aware of their responsibility to maintain their water and sewer service lines?

In the State of the Home Winter 2018 survey, 13 percent of respondents thought service lines are the responsibility of the municipality or utility, and 18 percent didn’t know who was responsible. Additionally, 11 percent thought their homeowners’ insurance would cover it. That means one-third either don’t know who is responsible or think the responsibility lies with their service provider, and more than 40 percent are not prepared for a break.

As unprepared as they are, they likely don’t know the three environmental factors that lead to plumbing failures: roots, cold and ground settling.

Roots

Sewer service lines are an especially tempting target for tree roots, since they’re a source of water, nutrients and oxygen the tree needs. Once a root has found a crack or loose joint, it will grow into the pipe, destroying it as it goes. During a drought, the water and nutrients in the sewer service line are an even bigger target. Tree roots generally extend up to two or three times the height of the tree, but can extend as far as seven times the height.

When roots worm their way in, their growth causes pressure at the crack or joint where they found their way in, worsening it. Clay and cast iron are particularly prone to root invasion, because their joints are loose-fitting and an easy target for roots. Most modern sewer lines are made of plastic pipes, which are more resilient, but there are still millions of homes that have older style sewer service lines – and they are reaching the end of their usable lifespans, roots or not.

Roots don’t need to destroy a sewer line to cause issues – as the root mass invades the pipe, growing larger, the mass itself will begin clogging the pipe, leading to slow-flowing drains and overflowing, neither of which are pleasant prospects for residents.

With most root intrusions, the first line of defense is using a plumbing auger, or “snake,” to clean out the line, using a bladed cutting tool on the end to power through roots and debris in the line, followed by root killer to discourage – but not entirely stop – future growth. However, some older lines, especially corrugated iron, have such thin walls that the cutting tool can damage them.

If a line is beyond what can be mediated with an auger, a plumber can line it with a plastic-and-cement sleeve or, in a worst-case scenario, dig a trench and replace the failed section of the line. This is the worst-case scenario, because it’s the most expensive, costing thousands of dollars.

Cold

Frozen water pipes impact a quarter million households each winter, and, while service lines are buried safely below the frost line, interior plumbing isn’t. If that plumbing is poorly insulated and exposed to quick drops in temperature, it can freeze.

Even a small crack in a pipe can lose hundreds of gallons of water a day, flooding a home and exposing it to structural damage and mold.

Surprisingly enough, it’s the warmer, southern states where homeowners are more vulnerable to frozen pipes. The reason is simple – northern home builders account for cold weather and insulate pipes and don’t put them in the danger areas, such as crawl spaces, outer walls, attics and garages. In addition, southern homeowners are less likely to be on guard for freezing pipes.

Pipes running through uninsulated spaces isn’t solely a southern problem – older homes in the north also may have issues with uninsulated pipes, and 37 percent of all pipe breaks occur in basements, a feature more likely to be found on the east coast. Whatever region a home is in, plumbers agree that 20 degrees Fahrenheit is the magic number for water line breaks caused by cold. It rarely gets so cold in the south, but when it does, those uninsulated pipes are in danger of freezing.

When the water in a pipe freezes, it expands, but this usually isn’t enough to cause a pipe to break – it’s the downstream pressure that now has no release, because of the ice blockage. This is why plumbers recommend opening all your interior taps – outdoor taps should have the water turned off – if you feel your pipes are in danger of freezing, because it reduces the pressure on your pipes.

In addition, homeowners can buy insulation sleeves that slip over their pipes to protect them. Anyone who is concerned about possible breaks can purchase sleeves at their local hardware store – they are much less expensive than the average $5,000 cost for interior plumbing breaks.

Ground settling

Pipes settle – a series of rain, freezing and thawing will cause ground movement and cause the pipes to move.

Most of the time, pipes should be fine, but older pipes can begin to leak at the joints and fittings. This will either attract roots, or, if it is a sewer line, soil from around the pipe can be washed into it, then into the sewer main, causing blockages and also a void around the pipe that can cause it to bow. If a sewer line begins sagging, it will trap water and debris in the sagging portion, and the debris will harden until it causes a blockage.

If water or sewage leaks into the soil surrounding the pipe, it can exacerbate the freeze-thaw cycle, causing increasing damage, and attract roots, which, as noted, are bad for pipes.

All underground pipes will be subject to shear forces, bending moments, curvatures and joint rotations caused by settling, but the ability to withstand it differs across types of pipe. Most homeowners won’t know there’s an issue until there’s a problem, and that’s often too late.

In the State of the Home survey, nearly 90 percent of respondents said municipalities should educate their residents about their service line responsibilities. At no cost to your municipality, you can offer protection to your residents and educate them not only on their service line responsibilities, but on a host of other plumbing issues through a partnership with the NLC Service Line Warranty Program. Municipalities may also receive royalties from the program. For more information visit Utility Service Partners, a HomeServe company.