There is nothing more frustrating than fixing a plumbing leak, only to have another one pop up three months later in a different part of the house. You start to feel like your house is falling apart. You blame the pipes, you blame the previous plumber, or you blame bad luck.
But in many cases, recurring leaks aren’t bad luck. They are a symptom of a systemic issue: High Water Pressure.
Imagine blowing up a balloon. If you fill it to 50% capacity, the rubber is relaxed and durable. If you fill it to 99% capacity, the rubber is stretched thin and stressed. One tiny poke will cause it to burst. Your pipes work the same way. If the water pressure coming into your home is too high, your entire plumbing system is operating in the “danger zone,” waiting for the weakest link to snap.
The “80 PSI” Red Line
Residential plumbing is designed to operate between 40 and 60 PSI (Pounds per Square Inch). Plumbing codes generally state that anything over 80 PSI is considered “excessive” and requires a regulator.
However, the municipal water pressure in many parts of Ventura County—especially in hilly areas like Thousand Oaks or Ventura hills—can be pumped as high as 120 or 150 PSI to ensure it reaches the fire hydrants at the top of the street.
To protect your home from this fire-hydrant pressure, there is a device on your main water line called a Pressure Reducing Valve (PRV). It looks like a brass bell sitting near your shut-off valve. Its job is to take that 120 PSI from the street and knock it down to a safe 55 PSI for your house.
When the PRV Fails
Like any mechanical device, PRVs wear out. The rubber diaphragm inside them hardens and cracks over time (usually every 10-15 years). When the PRV fails, it stops regulating.
Suddenly, that 120 PSI from the street is hammering directly into your home’s pipes. This creates “Water Hammer”—shock waves that travel through the water every time a valve closes.
The symptoms of a failed PRV include:
- Recurring Leaks: Especially pinhole leaks in copper or burst flex lines under sinks.
- Banging Pipes: A loud “thud” or shudder in the walls when the washing machine stops or the toilet fills.
- Dripping Faucets: The pressure forces water past the washers in your faucets.
- Running Toilets: The pressure overpowers the fill valve, causing the toilet to run constantly.
According to The Spruce, checking your water pressure is the single most effective preventative maintenance step a homeowner can take to avoid catastrophic pipe failure.
Fixing the Cause, Not Just the Symptom
If you call a handyman to fix a leak, they might just patch the pipe. They treat the symptom. But if the pressure is still at 110 PSI, the water will simply find the next weakest spot and burst there next week.
A professional leak detection and repair specialist always checks the pressure first. It is part of the diagnosis. If we find the pressure is high, we don’t just fix the leak; we replace the PRV.
This is the difference between a “Band-Aid” and a “Cure.” By replacing the PRV and resetting the pressure to a safe 55 PSI, we are instantly extending the life of every pipe, faucet, appliance, and seal in your entire house.
The “Thermal Expansion” Factor
There is a secondary pressure issue to watch for: Thermal Expansion. When your water heater heats up cold water, that water expands in volume. In a “closed system” (where you have a check valve or a functioning PRV), that extra volume has nowhere to go.
This causes pressure to spike dangerously high just after a shower, even if your PRV is working. The solution is an Expansion Tank—a small tank installed above the water heater that absorbs this extra volume.
If you are replacing a PRV, code often requires adding an expansion tank at the same time. This dynamic duo ensures your plumbing pressure remains smooth and constant, preventing the stress fractures that lead to floods.
Your Ventura County Experts for Leak Repair
Stop the cycle of recurring leaks. We diagnose the pressure problems that destroy plumbing.
Quest Leak Detection performs comprehensive pressure testing with every repair to ensure your system is safe. Visit our Leak Repair page to schedule a pressure check, or Contact Us to replace your failing PRV.
