How to Protect Your Home Foundation From Plumbing Leaks

How to Protect Your Home Foundation From Plumbing Leaks

Water leaks can wreak havoc on your home foundation.  Small leaks over time can slowly cause soils to swell all around the bottom of your foundation and may cause structural and cosmetic damage to your home.  If you think you have a foundation issue, it may be due to a plumbing leak—which can generally be divided into two categories:

  • Potable Water Leaks
  • Sewer Leaks

Both of these types of leaks can result in serious foundation issues for any homeowner. For example, the smallest of leaks in a potable water line (the size of the tip of a toothpick) can leak thousands of gallons over time.  And, sewer lines can leak for years on end without detection (especially the copper pipe sewer lines that were common for homes built in the 70’s and 80’s).  Unfortunately, if the sewer line is not located within an expansive clay layer, there may be no signs of a leak.

How can a Plumbing Leak Damage a Foundation?

If a potable water line or sewer line leaks enough into an active clay layer, the soils will swell, heave and lift up the foundation.  This can be seen as a bulge, dome or a high spot in the overlying slab.

When a foundation moves it can cause cosmetic damage to the structure.  The pattern of distress that results from a leak is sometimes a good indicator of what type of foundation issue is present.

How do Plumbers Test for a Water Leak?

Depending on what type of leak you may have, plumbers will most likely follow one of the below procedures.

Potable Water Leak Test:

  • First, a pressure gauge is attached to a spigot and the spigot is opened.  When water use is stopped, the gauge will show the pressure at which water is delivered from the street.
  • Second, the water meter is turned off.  If there are no leaks, the pressure on the gauge will remain constant.  If the pressure falls, it can be determined that water is leaking from the lines and is likely pooling and percolating into the soils beneath the foundation.

If a pressure drop is detected, the taps, toilets and other water nozzles are observed for drips or leaks.  If no leaks or drips are visually detected, the plumbing lines beneath the home should be checked for leaks.

Sewer Leak Test:
Like the potable water leak test, the sewer leak test follows a two-step process:

  1. The sewer line is blocked with a “balloon” at a location just outside of the foundation.
  2. The sewer line is then filled with water.  If the water level in the sewer drops, this means that a leak is present.  This test should be performed a few times to double-check.

For both of these tests, it’s important to remember that a leak test may not locate the exact source of the leak.  It only detects whether or not a leak is present.

How do Plumbers Locate Leaks?

Generally, sewer leaks are located with cameras that are pushed into the sewer lines.  As an alternative, leaks may also be detected by isolating and flooding individual sections of pipe.

For water line leaks, a listening device is normally used to locate the leak.

How Much Does it Cost to Fix a Leak?

Repair costs will depend on what type of leak you have. Below is some general guidance on what costs you can expect for a sewer and / or water line leak.

Sewer Leak Repair Costs:
Repairing sewer leaks can cost as little as $800 to over $20,000.  The range of cost depends on the condition of the lines and the nature of the problem.  In addition, homes with old deteriorate iron lines may require additional repairs in order to fix the deteriorated areas. A camera inspection with a location device will map the location of the leak and the line locations themselves, which will help determine the damage and cost.

Water Line Leak Repair Costs:
To repair a water line, it is likely that the plumber will need to break through the foundation and cut out the damaged pipe in order to install a new pipe.  This can be done for $1,000 or less.

If your home has a plumbing leak, it is recommended that you fix the leak and let the soils dry out (up to 12 months) before a pier plan is developed to support the foundation.  This way, the soils will have time to shrink back to their normal state before a relative elevation map is prepared.

For both sewer and water line leaks, it is very important to have a plumbing test performed after your foundation is repaired.

Crosstown Engineering representatives are trained to evaluate damage and prepare contour diagrams to help detect slab deformations that have resulted from plumbing leaks.  To learn more, contact us today.

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