A leaking supply or drain line under a slab does not just waste water. It puts a continuous point source of moisture into shrink-swell clay, and the clay lifts. On a Central Texas slab the leak is frequently the cause of the movement rather than a consequence of it.
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Six boxes, about thirty seconds. You pick when to be called back, and that is when the phone rings.
Or call (512) 729-9323Under a slab on high-plasticity clay, a leak is a localized irrigation system. The USDA official series description for Houston Black, whose type location is Travis County, reports 40 to 60 percent clay in the particle-size control section and high shrink-swell potential, with a profile more than 80 inches deep. Add water in one spot in that material and it expands in that spot. The result is heave — a dome centered on the leak — which reads on an elevation survey as a high area rather than a low one and produces cracks that open at the top and close at the bottom, the inverse of settlement. Diagnose it backward and you get piers installed to lift a slab that is already too high in the middle. The other jobs are on the services index.
Pressurized supply lines under a slab leak continuously and at volume. The tells are a water bill that stepped up without a change in habits, the sound of running water with every fixture closed, a warm spot on the floor when the leak is on the hot side, and unexplained damp flooring. Drain and sewer lines are not pressurized, so they leak only when something is being used. Their tells are slower: recurring backups, a smell in one part of the house, and soil erosion under the slab that eventually produces a void rather than heave. Both need to be separated from surface water arriving over the edge of the slab, a grading problem covered in drainage and grading, and from moisture wicking through concrete, which is a vapor problem rather than a leak.
The Texas Section ASCE guidelines make the test a required step whenever a slab is going to be moved: water supply and sanitary drain lines should be tested for leaks if jacking or lifting is included in the remedial measures, and gas service lines may require adjustment. That is why a foundation proposal without a plumbing test line item is incomplete. Supply lines are isolated at the meter and held under pressure to see whether the system holds. Drain lines are isolated at their low point and filled with water to a defined level so the surface can be watched for a drop. Where a test fails, locating the break before breaking concrete keeps the repair small, and that is done with cameras run through the line, with acoustic and pressure equipment on the supply side, and with tracing gas where a supply leak will not localize.
Texas sets the scope of a standard real estate inspection in the administrative rules, and the limits matter if you are relying on an inspection report. Under 22 TAC 535.231 the inspector shall report static water pressure and the presence of active leaks, but is not required to inspect for sewer clean-outs, verify the performance of floor drains, or pressurize or test the gas system. So a clean inspection report is not a statement that the lines under the slab hold. That is a separate test, and on a house with movement on a clay lot it is the test that should be bought first, before any repair scope is written.
Once a leak is found, the repair falls under Austin's trade permit process, and the city is specific about who may hold the permit. Stand-alone trade permits can only be obtained by licensed professional trade contractors or by a qualified homeowner acting as their own trade contractor under the city's Homestead Permit requirements. The city's plumbing permit form adds that where a building permit applies, that permit has to be issued before the trade permit is, and that a permit expires on the 181st day if no inspection has taken place. The same form carries the tree rule: installing utilities within the critical root zone of a regulated tree requires a Tree Ordinance Review Application, a live constraint when a service line has to be dug up beside a mature oak.
There are three. Spot repair through the slab: cutting an opening, excavating to the line, replacing the failed section and restoring the concrete. Tunneling from outside, which reaches the same point without cutting the interior floor and is priced by the linear foot. Or reroute, which abandons the under-slab run and carries the line overhead or around the perimeter, usually the right answer on an older galvanized or cast-iron system where the failure is age rather than one bad joint. The decision follows how many breaks the camera finds and what the pipe material is.
Stopping the leak does not undo the movement. Clay that has been wet for a long time consolidates as it dries out again, and the shape it comes back to is not necessarily the shape it started in. So the sequence is: test, repair the plumbing, re-survey floor elevations after a drying period, and only then decide whether structural work is warranted. The measurement side is covered under foundation inspection.
Slab Moisture and Plumbing Leaks in Austin. Call (512) 729-9323 and a technician is dispatched with the parts on the truck. You get the price before the work starts.
Call (512) 729-9323The City of Austin's study updating the rainfall period of record puts Camp Mabry annual extremes at 11.52 inches in 1954 and 64.68 inches in 1919 against an 1856-2012 mean of 33.4 inches, and records only 0.05 inches of rain between June 22 and September 16 in 2011. The city's watershed report logged 2.96 inches in one hour at Camp Mabry after 51 consecutive days with no measurable rainfall.
Why it matters: Expansive clay damages foundations through moisture cycling, and this is the measured amplitude of the cycle that Austin foundations are asked to ride.
Sources: services.austintexas.gov · austintexas.gov
The City of Austin's small project retaining wall instructions state that any retaining wall over four feet in height located inside the city limits requires a building permit under Section 25-11-34 of the Land Development Code, that the small project path covers walls less than 100 feet long and 8 feet high, that backfill cannot exceed two feet in depth unless it occurs for no more than four feet measured horizontally behind the wall, and that no more than four feet of cut is allowed in front of the wall.
Why it matters: Height is the trigger for permitting on retaining wall work, and the cut and backfill limits decide whether a repair can use the small project path at all.
Sources: austintexas.gov · austintexas.gov
The USGS description of the Austin quadrangle divides the area into a higher western district of the Edwards Plateau and a lower eastern district at the Coastal Plain margin. The Balcones escarpment runs through the Austin area as a major topographic and structural boundary.
Why it matters: A house west of the divide can encounter shallow limestone while an east-side lot may have a very different soil profile. An Austin foundation assessment has to follow the actual lot and structure rather than applying one repair method across the city.
Source: pubs.usgs.gov
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