Plumbing across Greater Houston

The ground under Houston, and what it does to pipe

Most of Greater Houston sits on Beaumont clay, locally, gumbo. It is highly plastic: it takes on water and swells, dries and shrinks, and does so unevenly depending on where the shade falls, where the downspouts drain, and which tree is pulling moisture out of which corner of the lot. Between a wet spring and a dry August the vertical movement across a single slab can be measured in inches rather than fractions.

A concrete slab moves with that. Copper supply lines cast into it, and cast iron or clay drain lines beneath it, do not want to. What gives way is a joint, a fitting, or the pipe wall where it passes through the slab edge. This is why slab leaks are routine work here rather than an unusual event, not because the plumbing was installed badly, but because rigid pipe was buried in soil that behaves like a slow hydraulic ram.

The second local factor is the water table. Across much of Harris and the coastal side of Fort Bend and Liberty counties, groundwater sits close enough to the surface that any excavation below the slab fills. That has practical consequences: a tunnel dug to reach an under-slab line needs pumping while the work happens, and a leak that has been running for weeks has often been feeding water into ground that was already saturated. It also means the classic symptom, a warm or damp patch on the floor, can be muted, because the water leaves sideways rather than upwards.

Subsidence is the third. Decades of groundwater withdrawal have lowered ground level significantly in parts of the region, and while the regulated districts have slowed it, differential settlement between a house and the utilities entering it is a real and continuing source of separated drain joints and sheared service lines.

Housing stock: five build eras, five different problems

Pre-1950, inside the Loop and the older town centres. Pier and beam, galvanised supply that has long since scaled shut from the inside, and cast iron drain lines that are at or past the end of their working life. The good news is access: a crawlspace makes both diagnosis and repair dramatically cheaper than the same job under a slab.

1950s to early 1970s. The great slab-on-grade expansion. Copper supply under the slab, cast iron below it. Both are now old enough to fail on their own schedule, and the soil movement above accelerates it. Most of the slab leak and cast iron replacement work in the region is on houses from this window.

Mid 1970s to 1980s. Cast iron gives way to PVC drains, which is a genuine improvement. Supply is copper, sometimes with the earliest polybutylene appearing towards the end of the period.

1990s. The polybutylene decade in the outer suburbs, grey flexible pipe with plastic or copper insert fittings, whose failure mode is a fitting letting go without warning. If your house is from this period and nobody has repiped it, it is worth finding out what you have before it decides for you.

2000s onward. PEX supply, PVC drains, tankless heaters increasingly common, and manifolds in the wall rather than a tree of copper in the slab. The failures here are usually workmanship or fixtures rather than material fatigue, and they are the cheapest of the lot to put right.

What we are actually called out for here

Slab leaks, year round, with a spike after the first sustained dry spell. The soil pulls away from the slab, the slab flexes, and something that had been holding gives up. The symptom is often a water bill before it is a wet floor.

Cast iron drains that have run out of pipe wall. Sixty-year-old cast iron in this soil scales, then thins, then bellies where the ground beneath it has settled. Camera footage settles the question of whether it needs cleaning, lining or replacing far more reliably than symptoms do.

Root intrusion, all year. Long growing season, live oaks and water oaks with aggressive root systems, and clay soil that cracks in drought and gives roots a path. They enter at a joint and grow towards the only reliable water in a dry August, which is your sewer line.

Storm-season backups. Heavy, fast rainfall on saturated ground puts pressure on municipal systems, and where a private line has a defect the surcharge finds it. A line that backs up only during a storm is telling you something specific.

Freeze damage, rarely but severely. Houston is not built for hard freezes, which is exactly why one does so much damage when it arrives, attic runs with minimal insulation, exposed hose bibs, and unprotected pipe in unconditioned garages. February 2021 was the demonstration.

Water heaters in attics. Common in two-storey construction across the region, and the worst possible location for a tank to fail. A pan and a live drain line are not optional details up there.

Water chemistry and what it does to fixtures

City of Houston water is predominantly surface water from Lake Houston, Lake Conroe and the Trinity River system, treated to a moderate hardness, noticeable on glass and in kettles, not aggressive. It is manageable without treatment for most households, though a softener still extends the life of a tankless heater materially.

Move out into Montgomery, Waller, Grimes and San Jacinto counties and the picture changes: groundwater from the Gulf Coast aquifer, often considerably harder, sometimes with enough iron or sulphur to be obvious at the tap. Scale in a tankless unit becomes a maintenance interval rather than a footnote, and a softener stops being optional if you want the heater to reach its expected life.

On a private well, common through the northern and eastern parts of the region, the whole system is yours: pump, pressure tank, and whatever treatment sits after it. Pressure that swings, a pump that cycles rapidly, or air spitting at a tap are all pointing at the tank or the pump rather than the plumbing indoors.

How fast we can be there

Coverage is dense across Harris County and the inner ring of Montgomery and Fort Bend, so same-day is the normal outcome and genuine emergencies, water running, sewage indoors, no water at all, go to the front of the queue. Traffic is the real variable inside the Loop, and we would rather tell you two hours and arrive in ninety minutes than the reverse.

Further out into Liberty, Waller, Walker, Grimes, San Jacinto and Austin counties, same-day is usual but depends on where the nearest truck already is. You will get a real window on the phone, and if the honest answer is first thing tomorrow, you will hear that along with what to shut off in the meantime.