Low Water Pressure in Round Rock Homes: Causes and Fixes

Low water pressure in a Round Rock home almost always comes down to one of five causes: a failed pressure-reducing valve (PRV), clogged aerators or fixtures, hard-water scale narrowing supply lines, a leak somewhere in the system, or temporary municipal supply issues. Each has a different fix, and figuring out which one you have determines whether the repair is $25 or $5,000.

This guide walks through diagnostic order.

What Normal Pressure Looks Like

Healthy residential water pressure is 45-75 PSI. Below 40 PSI, fixtures feel weak. Above 80 PSI, code requires a PRV to prevent damage to pipes and appliances.

Round Rock municipal supply typically arrives at the meter at 80-120 PSI — too high to use directly, which is why most homes have a PRV at the main shutoff.

Test your pressure with a $10-15 pressure gauge that threads onto a hose bib. Open the bib, read the gauge after pressure stabilizes (10-15 seconds).

Diagnostic Order

1. Test One Fixture vs. All Fixtures

The single most useful question.

Only one fixture is weak: local issue. Likely aerator, supply line, valve, or fixture itself.

All fixtures are weak: system issue. PRV, leak, scale buildup, or municipal supply.

2. Check the Aerator (Single-Fixture Weakness)

Aerators are the small mesh screens at the end of faucets. They catch debris, scale, and sometimes pipe debris.

Unscrew the aerator (often hand-tight) and inspect. White flakes are scale, often easily rinsed. Dark debris is sediment. Some aerators clean up easily; some need replacement ($5-15 at any hardware store).

Showers have a similar component — the showerhead itself often has a small screen at the inlet that scales up.

This is the most common single-fixture cause in Round Rock because of our hard water.

3. Check the PRV (Whole-Home Weakness)

The pressure-reducing valve is a brass valve typically located at the main shutoff where city water enters your home. Its job is to reduce the high municipal pressure (80-120 PSI) down to a safe house pressure (50-70 PSI).

PRVs fail in two ways:

Pressure creeps up (PRV failing open) — high pressure stresses pipes and appliances
Pressure drops (PRV failing closed/restricted) — what we are looking at here

If the static pressure at a hose bib reads under 40 PSI, the PRV is likely failing. Replacement runs $250-550. See our PRV guide for full diagnostic detail.

4. Look for Leaks

A leak diverts water away from fixtures, reducing flow. Two diagnostic approaches:

Visual inspection. Walk the home — look under sinks, behind toilets, at appliance connections, at the water heater base.
Water meter test. Turn off everything. Note the meter reading. Wait 30 minutes. Re-read. If it has moved, you have a leak.

If you suspect a hidden leak (slab, behind walls), see electronic leak detection.

5. Consider Hard-Water Scale in Lines

Decades of hard water plate calcium scale onto the inside of pipes, especially galvanized steel and old copper. Over time the effective inside diameter shrinks.

If your home is 30+ years old, has not been repiped, and pressure has gradually declined over years, scale is likely a contributor. The fix is whole-home repiping — there is no way to descale long buried lines.

6. Municipal Issues (Temporary)

Occasionally the issue is on the city side:

Main break in your neighborhood
Maintenance flushing
Service interruption
Pressure variation during peak use times

The City of Round Rock Utilities publishes outage and maintenance notifications. Call 512-218-5555 if you suspect a municipal issue.

Specific Round Rock-Common Scenarios

Older Subdivisions (30+ years old, original galvanized)

Symptoms: gradually declining pressure over decades, all fixtures affected, rusty-tinted water occasionally.

Likely cause: scale and corrosion in supply pipes.

Fix: whole-home repipe (typical $4,500-10,000 PEX).

Newer Homes (post-1995, sudden drop)

Symptoms: pressure was fine, then suddenly low.

Likely cause: PRV failure, or municipal issue, or new leak.

Fix order: test pressure at hose bib, check PRV, then leak diagnosis.

Single Bathroom Affected

Symptoms: only the master bath has weak pressure.

Likely cause: shutoff valves not fully open after recent work, fixture-specific issue, scale in the supply line to that bathroom.

Fix: open shutoffs fully, clean aerators, check shower mixer cartridge.

Hot Side Only

Symptoms: cold water is fine, hot water is weak.

Likely cause: scale or sediment buildup at the water heater outlet, hot-side shutoff partially closed, dip tube failure.

Fix: drain and flush water heater; replace dip tube if needed; verify hot-side shutoff.

Fixing the Most Common Causes

| Cause | Typical fix cost (Round Rock) |

|---|---|

| Clogged aerator (DIY) | $5-15 part |

| Clogged aerator (plumber) | $75-150 |

| Failed PRV | $250-550 |

| Single leaking supply line | $250-650 |

| Slab leak | $1,500-5,000 |

| Whole-home scale (repipe) | $4,500-12,000 |

| Showerhead/valve cartridge | $50-250 |

When to Just Call

If you have ruled out obvious local fixes (aerator, single-fixture issues) and the pressure is still low, call. Hidden leaks and PRV failures get expensive the longer they go unaddressed.

Schedule a pressure diagnostic or general plumbing service.

Service Area

Pressure diagnosis and repair throughout Round Rock, Cedar Park, Pflugerville, Georgetown, and Hutto.