Plumbing across Greater San Antonio

The hardest water most Texans will ever plumb

San Antonio draws heavily on the Edwards Aquifer, water that has spent a long time in limestone and arrives carrying a lot of dissolved calcium and magnesium. Hardness across the service area commonly runs in the range that water chemists describe as very hard, and unlike most plumbing variables it affects every single water-carrying component in the building at once.

What that looks like in practice. A storage water heater accumulates a layer of scale on the element or across the tank bottom; the burner or element then has to heat through it, efficiency drops each year, and the tank fails earlier than its rating. A tankless unit is worse, because the heat exchanger has narrow passages and scale narrows them further. An undescaled tankless heater on San Antonio water can lose years off its life and will usually throw flow or temperature faults before it dies. Shower cartridges seize. Aerators block. Fill valves in toilets stop sealing because the seat has calcified. Angle stops that have not been turned in a decade weld themselves open.

The remedy is unglamorous and effective: a properly sized softener, and a descaling interval on any tankless unit. Homeowners here who fit a softener generally notice it first in the shower and second on the day their neighbour replaces a heater they themselves are still using.

North into Comal and Kendall, and west into Medina and Bandera, wells are common and hardness climbs further, sometimes with iron or sulphur alongside. That moves treatment from worthwhile to necessary.

Rock to the north, moving clay to the south and east

San Antonio sits on the Balcones Escarpment, and the ground changes character as you cross it.

North and northwest, Stone Oak, Hollywood Park, Helotes, Boerne, Fair Oaks Ranch, Canyon Lake, is limestone, often shallow and often karst, meaning fissures, voids and solution channels rather than uniform rock. Soil movement is minimal, so slab leaks caused by heave are uncommon. What is common instead is expensive excavation: reaching a sewer line under shallow rock is slow work, which is why trenchless lining and bursting frequently price better than open-cut out there. Karst also means water travels unpredictably underground, so a leak can surface a surprising distance from its source.

South and east, the South Side, southern Bexar, Wilson, Guadalupe and Gonzales counties, moves onto expansive clay that behaves much more like Dallas or Houston. Slab movement returns as a real factor, and with it slab leaks, foundation-related drain failures and the whole under-slab repair conversation.

The result is that a house in Stone Oak and a house in Southside get genuinely different diagnostic starting points, and the address tells us a lot before we arrive.

Housing eras across Bexar County

Pre-war and pre-1950, King William, Monte Vista, Alta Vista, Government Hill, Dignowity Hill. Pier and beam, original galvanised supply now heavily scaled from the inside, and cast iron drains at the end of their service life. Access underneath makes work affordable; the age of the material makes replacement the usual honest answer.

1950s to 1970s. Post-war and military-era expansion around the bases and out along the northeast and northwest, slab-on-grade, copper supply in the slab, cast iron below it. These are the houses generating most of the region's slab leak and cast iron replacement work.

1980s and 1990s. PVC drains, copper then polybutylene supply as the northern suburbs and the Comal and Guadalupe county corridors filled in. Polybutylene is present in enough 1990s stock here to be worth checking for.

2000s onward. PEX and PVC, tankless heaters common, and attic installations standard in two-storey construction. On this water, a tankless unit installed without treatment or a maintenance plan is the most predictable early failure in the region.

What we get called for here

Water heaters, constantly. More heater replacement per household than most Texas markets, and the reason is entirely the water chemistry. A heater that would give twelve years elsewhere gives eight or nine here if nothing is treating the supply.

Softener installation and repair. A large share of houses have one; a meaningful share of those have one that stopped regenerating years ago and is now simply a restriction in the line. If your water went hard again and nobody has touched the unit, that is usually why.

Slab leaks on the south and east sides. Standard expansive-clay pattern, standard diagnosis: meter test, pressure isolation, then acoustic or thermal location before anything is opened.

Tankless faults that are actually scale. Error codes, fluctuating temperature, reduced flow. Descaling resolves a surprising proportion of what gets reported as a failed unit.

Root intrusion in older neighbourhoods. Mature live oaks and pecans over sixty-year-old clay and cast iron laterals. Long growing season, so it is year-round work.

Freeze damage, in bursts. Hard freezes are less frequent here than in North Texas but they happen, and the building stock is no more prepared for them. Exposed hose bibs, attic runs and exterior tankless units are where the splits appear.

Response across the region

Bexar County coverage is dense and same-day is the normal outcome, with emergencies prioritised over scheduled work. The northern corridor into Comal and Kendall, New Braunfels, Boerne, Canyon Lake, is well covered and usually same-day.

Out into Medina, Atascosa, Bandera, Kerr, Gillespie, Wilson and Gonzales counties the distances get real, and so does the honesty about them. You will get an accurate window on the phone, plus what to isolate while you wait. If the answer is tomorrow morning, we will say tomorrow morning rather than let you sit up hoping.