# Repiping in Northwest Austin: Northwest Hills, Great Hills, Jester and River Place > Repiping in Northwest Austin: slab leaks and overhead reroutes in 1970s and 1980s houses on limestone, high pressure, West Lake Hills and Rollingwood. URL: https://gracklerepipingaustin.com/service-areas/northwest-austin/ ## What starts a repipe in Northwest Austin Ticket A Slab leak ### A leak under a slab that sits on rock Limestone barely moves, so the cause is usually the pipe itself. Breaking rock-backed concrete to reach it rarely beats rerouting overhead. Ticket B Pressure ### A relief valve dripping at the water heater 78730 and 78731 rank near the top of Austin for regulator permits. Static pressure above 65 psi means a regulator and expansion tank. Ticket C Copper ### Pinholes in a 1980s copper system 78750 and 78759 have the highest shares of 1970s and 1980s houses in Austin. Repeat pinholes in copper of that age point to the whole system. Ticket D Small city ### A house in West Lake Hills or Rollingwood Both are separate cities with their own permit rules, so the permit office and code change at the city line. ## Services in Northwest Austin ### Slab leak reroutes A leaking water line under the slab is confirmed, capped and abandoned, then replaced with a new line run overhead through the attic and down the walls. Details → ### Copper repiping A whole-house or partial repipe in rigid copper tube, joined by soldering or press fittings and routed for the access a rigid pipe needs. Details → ### Whole-house repiping Every hot and cold supply line from the main shutoff to the fixtures replaced, permitted under Austin's plumbing code, pressure tested and patched. Details → ### PEX repiping A whole-house or partial repipe in PEX tubing, with the tubing type, fittings and layout chosen for the house and run to Austin's attic and pressure rules. Details → ### Water line replacement The buried yard line from the meter to the house replaced by trench or bore, with a new customer valve, a permit and a pressure test before backfill. Details → Northwest Austin has as many water reroute permits as any part of the city, and the reason is not the one people expect. From October 2021 to October 2026, 78731, 78750, 78759 and 78730 logged 36 reroutes and 26 water repipes, yet the permit locations sit almost entirely on shallow limestone, where the soil barely moves. A slab leak here is a pipe problem, and rock under the yard and the slab shapes the fix. [Grackle Repiping Austin](https://gracklerepipingaustin.com/) plans and manages repipes and slab-leak reroutes in Northwest Hills, Highland Hills, Great Hills, Balcones Woods and Jester Estates. The pipe work itself is carried out by licensed and insured plumbing contractors, with the Austin permit in the name of a City-registered responsible master plumber. This page also covers West Lake Hills and Rollingwood, two small cities just south with their own permit offices. ## A 1970s and 1980s housing belt The housing here is concentrated in two decades. Census figures put 61.7% of homes in 78750 between 1970 and 1989, the highest share of any Austin ZIP code, along with 57.7% in 78759 and 48.7% in 78731. Houses of that era were commonly built on slabs with copper supply lines running under or through the concrete, and where those lines are original, they have been carrying water for decades. 78731 is the exception in part. Around Highland Hills and the streets below Mount Bonnell, about a quarter of its homes were built before 1970, galvanized pipe appears in City permit descriptions, and Austin Water flags 29 service lines there as galvanized requiring replacement. It also leads the area in water repipe permits, with 14, alongside its 12 reroutes. 78750 matches those 12 reroutes, and only 78749 has more. ## Slab leaks on limestone On the clays of east and south Austin, a slab leak often comes with talk of the ground moving. That explanation fits poorly here. The federal soil survey maps Eckrant and Brackett soils at most of the repipe and reroute permit locations in these ZIP codes. Eckrant is a very shallow soil over hard limestone, with bedrock four to twenty inches down. All 12 locations in 78759 and all 5 in 78730 rate low for shrink-swell, and 78731 has just 1 high-rated location out of 25. So the cause is usually in the pipe. Copper can pinhole from the inside, hot water lines expand and contract and wear where they pass through concrete, and high static pressure adds stress at every fitting. When one line under the slab fails, others of the same age and material are carrying the same history. The [copper pinhole leak guide](https://gracklerepipingaustin.com/guide/copper-pinhole-leaks/) explains how those leaks start, and the [guide to slab leak repair or reroute](https://gracklerepipingaustin.com/guide/slab-leak-repair-or-reroute/) covers when a single fix is enough. ## Rock pushes the fix overhead Opening a slab to reach a leak means breaking concrete, digging out what is under it and patching both, and on rock that digging is slow. Rerouting avoids it. The failed run is cut off and sealed at the point where it drops into the floor, and fresh pipe is carried across the attic and dropped inside a wall to the same fixture. More than half of Austin’s water reroute permits mention the attic, overhead runs or the ceiling. The [slab leak reroute page](https://gracklerepipingaustin.com/slab-leak-reroute/) describes the work. Where several lines have failed, or where copper is pinholing in more than one place, rerouting one line at a time stops making sense, and a whole-house repipe through the attic replaces the system in one permit. In two-story houses, upstairs fixtures are fed from the attic and downstairs lines drop through walls or chases. The choice of pipe matters on long runs: a [copper repiping](https://gracklerepipingaustin.com/copper-repiping/) job keeps metal throughout, while a [PEX repipe](https://gracklerepipingaustin.com/pex-repiping/) uses fewer fittings. The [PEX vs copper guide](https://gracklerepipingaustin.com/guide/pex-vs-copper/) sets out the trade-offs without declaring a winner. Rock matters outside the house too. Where a yard line needs replacing, trenching through limestone is harder than through soil, which can tip the route or method. The soil survey also rates these limestone soils highly corrosive to uncoated steel, which is worth knowing where an old galvanized yard line is still in the ground. Texas 811 does not mark private lines that serve only the owner, so those are traced before digging. The [water line replacement page](https://gracklerepipingaustin.com/water-line-replacement/) covers the options. ## Pressure on the hills The hills west of MoPac carry some of the highest regulator activity in Austin. Measured against the number of homes, City plumbing permits naming a regulator run 29.9 per 10,000 units in 78730, 25.7 in 78731 (39 permits), 22.0 in 78750 and 17.1 in 78759. All four ZIP codes are also on the list for Austin Water’s program that swaps out old polybutylene service pipe on the utility side, a program aimed first at lines under more than 105 psi. It stops at the meter; the owner’s yard line and the house piping are untouched. Austin’s local plumbing rule sets the line at 65 psi: above that static pressure, the house needs an approved regulator with a strainer that brings pressure down to 65 psi or less, and a thermal expansion tank on the house side of it (section 608.2 as amended by the City). Regulators wear out, and a failed one passes full street pressure straight through, which shows up as a dripping relief valve at the water heater or banging when a valve shuts. A gauge reading on the hose bib settles whether a regulator, a tank or both belong on the estimate, and the [guide to pressure reducing valves](https://gracklerepipingaustin.com/guide/pressure-reducing-valve-austin/) covers how they age. ## West Lake Hills & Rollingwood West Lake Hills and Rollingwood sit just south of this area across Lake Austin, and both are separate cities. Their housing is older than the surrounding suburbs: census figures put 41.2% of Rollingwood’s homes and 31.3% of West Lake Hills’ before 1980. Both stand on the same Brackett and Eckrant limestone soils, so the slab-leak and rock-trenching logic above applies, but the permit path does not. West Lake Hills runs its own building department. The city has adopted the 2021 International Code Council codes, takes permits through MGO Connect and offers a Small Project Application for single projects; its [Building and Development page](https://www.westlakehills.org/95/Building-Development) has the current forms. Because its plumbing code is from the International family rather than Austin’s Uniform Plumbing Code, the code sections on an estimate change at the city line. Rollingwood operates its own water distribution system, separate from Austin Water, and its permit rules are confirmed per address before work is scheduled. The water provider for a West Lake Hills address is confirmed per address as well. ## Estimate, permit and inspection Before a price is written, the walk-through identifies the pipe material in more than one spot, takes the static pressure reading, checks how much room the attic gives and marks the walls that can be opened. For a slab leak, the next step is confirming that the leak is on a supply line and not a drain. On the written estimate, the permit, the pressure test and the wall patching each get their own line, and the [Austin repipe permit guide](https://gracklerepipingaustin.com/guide/repipe-permit-austin/) explains who is allowed to pull that permit. The house has water again at the close of every work day. Once the new system holds its pressure test and passes the City’s inspection, the walls are closed; old pipe within reach is taken out and the rest is sealed off and left in place. ## East of MoPac and up US 183 East of MoPac, [North Central Austin](https://gracklerepipingaustin.com/service-areas/north-central-austin/) has older galvanized houses on firmer soil. Up US 183, [Cedar Park](https://gracklerepipingaustin.com/service-areas/cedar-park/) uses its own permit office and unsoftened Lake Travis water. [South and Southwest Austin](https://gracklerepipingaustin.com/service-areas/south-austin/) shares the reroute pattern and the high pressure, with clay in 78745 and limestone in 78749. ## Neighborhoods and coverage - Northwest Hills - Highland Hills - Great Hills - Balcones Woods - Jester Estates - River Place ### Landmarks - Mount Bonnell - Bull Creek District Park - The Arboretum - Pennybacker Bridge ### Routes - MoPac (Loop 1) - Loop 360 (Capital of Texas Highway) - US 183 (Research Boulevard) - RM 2222 - Spicewood Springs Road - Far West Boulevard - Anderson Mill Road 1. 1. Cedar Park 2. 2. East Austin 3. 3. Georgetown 4. 4. Kyle 5. 5. North Central Austin 6. 6. Northwest Austin 7. 7. Round Rock 8. 8. South Austin 9. 9. South Central Austin ## Northwest Austin questions ### How much does a repipe cost in Northwest Austin? A typical Austin-area range for a whole-house repipe is $4,500 to $15,000+, and about $4,500 to $9,000 for PEX with typical access; a slab leak reroute runs about $4,000 to $9,750 before leak detection. Two-story houses, long overhead runs, copper and a regulator with an expansion tank push a job toward the higher end. ### Why do slab leaks happen in Northwest Austin if the ground hardly moves? Because the pipe fails on its own. Copper laid under 1970s and 1980s slabs can pinhole from the inside, hot lines expand and rub where they pass through concrete, and high static pressure adds stress at every joint. The shallow limestone here does not heave like clay, so the cause sits in the pipe, not the ground. ### Can a new water line be trenched through the limestone in Northwest Austin? It can, but rock makes trenching slower and costlier than in soil, which is one reason slab leaks here are rerouted through the attic. For a yard line, rock pushes the choice of route and method. Texas 811 does not mark private lines that serve only the owner, so those are located separately before digging. ### Who issues the plumbing permit in West Lake Hills or Rollingwood? Each city handles its own permits. West Lake Hills has adopted the 2021 International Code Council codes and takes permits through MGO Connect, with a Small Project Application for single projects. Rollingwood's permit rules are confirmed per address before work is scheduled. ### Do older houses near Mount Bonnell have galvanized pipe? Some do. 78731 has older pockets, with about a quarter of its homes built before 1970, and Austin Water flags 29 service lines there as galvanized requiring replacement. Galvanized pipe also shows up in City permit descriptions there. The walk-through checks the material at several points before any scope is set. ## Related guides - Decision Guide [Should a slab leak be repaired or rerouted?](https://gracklerepipingaustin.com/guide/slab-leak-repair-or-reroute/)Three ways to fix a leaking water line under a slab, and the conditions that make each one the sensible choice: how many leaks, what the pipe is, what is on the floor and what the attic allows. - Learn [What causes a pinhole leak in copper pipe, and when is it time to repipe?](https://gracklerepipingaustin.com/guide/copper-pinhole-leaks/)A pinhole in copper is the last step of a wall slowly thinning from the inside or outside. This guide explains the mechanisms, what they look like, what Austin's water and soil add, and how the leak pattern decides between a repair and a repipe. - Learn [Do I need a pressure reducing valve in Austin?](https://gracklerepipingaustin.com/guide/pressure-reducing-valve-austin/)Austin's plumbing code sets the line at 65 psi: above it, a house needs a pressure reducing valve with a strainer and an expansion tank after it. Here is how the rule works, how a valve fails, and how it fits into a repipe. - Decision Guide [PEX vs copper: which pipe should an Austin house be repiped with?](https://gracklerepipingaustin.com/guide/pex-vs-copper/)Neither pipe wins everywhere. This guide compares PEX and copper on the things that decide an Austin repipe: price and access, attic heat and freeze, the water your utility delivers, joints and the layout of the house. - Learn [Do I need a plumbing permit to repipe a house in Austin?](https://gracklerepipingaustin.com/guide/repipe-permit-austin/)A repipe in Austin is permitted work. This guide covers who can pull an Austin plumbing permit for a repipe, what the inspector checks and when, what a failed inspection costs, and how the rules change in Round Rock, Cedar Park, Georgetown, Kyle and the other suburbs. ## Nearby service areas - [North Central Austin](https://gracklerepipingaustin.com/service-areas/north-central-austin/)Postwar galvanized lines; Austin Water replaces flagged galvanized service lines - [Cedar Park](https://gracklerepipingaustin.com/service-areas/cedar-park/)Lake Travis water without lime softening (183 ppm hardness) and permits under the 2021 IPC - [South Austin](https://gracklerepipingaustin.com/service-areas/south-austin/)Most water reroute permits in Austin; high static pressure on the southwest side