Same-Day Service
Most service calls handled same-day across Spokane and Coeur d'Alene.
Pressure & Backflow
The valves that protect your home's water supply.
Water pressure that’s too high damages fixtures, water heaters, and appliances. Pressure that’s too low makes showers and dishwashers feel weak. And backflow — water flowing the wrong direction through your home’s supply — can contaminate drinking water. The valves that manage all three live behind the scenes, and most homeowners never think about them until they fail.
Our certified backflow assembly testers handle annual testing required by Spokane and Coeur d’Alene water utilities, plus full repair and replacement of pressure-reduction valves (PRVs), pressure vacuum breakers (PVBs), and double-check valves. Same flat-rate, written-quote process.
- Certified testers State-certified backflow assembly testers — required for annual certification.
- Pressure diagnostics Static + dynamic pressure tests at multiple points — find the real cause.
- Flat-rate quotes Approved before any work — never charged by the hour.
- Warrantied work 1-year labor warranty plus full manufacturer parts coverage.
When to Call
Pressure and backflow warning signs
Pressure problems show up in dozens of small ways before causing real damage. Watch for these:
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Banging pipes (water hammer)
High pressure or a failing PRV — both cause noisy pipes and shortened fixture life.
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Weak shower or faucet
Low system pressure can mean a stuck-closed PRV, a partial blockage, or a hidden leak.
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Toilet refills on its own
High pressure leaking past flappers and fill valves — wastes water and shortens toilet life.
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Leaking pressure-relief valve
PRV failure or thermal expansion — needs immediate attention.
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Backflow test notice from utility
Spokane and Coeur d'Alene utilities require annual testing of certain backflow assemblies.
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Discolored water from outdoor tap
Possible backflow event — get the assembly tested and the line flushed.
What We Do
Pressure and backflow service in detail
Testing, repair, replacement, and certification — handled by state-certified testers.
- Backflow Prevention Test, repair, and replace double-check valves, RP assemblies, and air gaps — annual utility-required certification included.
- Pressure Reduction Valve Repair PRV diagnosis, rebuild, and replacement — fixes water hammer, fixture wear, and high-pressure-related leaks.
- Pressure Vacuum Breaker PVB testing and repair on irrigation systems — required certification for connection to municipal water.
- Water Pressure Diagnostics Static and dynamic pressure testing at multiple points — find the real cause of weak or surging pressure.
- Thermal expansion tanks Required on closed systems with a PRV — protects water heaters and fixtures from over-pressure.
- Annual certification Utility-required annual backflow testing with documentation filed for you.
- Water hammer remediation Pressure reduction, air-chamber install, and fixture-level water-hammer arrestors.
- Code-compliance review Make sure your backflow assemblies meet current Washington and Idaho plumbing code.
How It Works
Our pressure service process
Test first, repair second. We don't replace what doesn't need replacing.
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Call & schedule
Most pressure and backflow service scheduled within 24–48 hours.
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Test & diagnose
Pressure readings at multiple points, backflow assembly test, and a written report.
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Approve the price
Repair, rebuild, or replace — flat-rate quotes for each option.
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Service & certify
Most jobs done same-visit. Certification paperwork filed with the utility.
Current Specials
Save on the work your home needs most.
Why Choose Mainstream
Upfront Pricing
Flat-rate pricing approved before work begins — no surprises on the invoice.
Licensed & Insured
Fully licensed in Washington and Idaho, bonded, and insured for your protection.
Satisfaction Guaranteed
If it isn't right, we make it right. Period.
Annual backflow test or pressure problem? We can help.
Same-day service across Spokane & Coeur d'Alene — flat-rate pricing, no surprises.
What Our Customers Say
Don't just take our word for it — hear from our satisfied customers
★★★★★
Ricky Saldana the technician that came out was fantastic. He was so knowledgeable about my plumbing issues and his recommendations were spot on. He was on time and very pleasant to work with. I would highly recommend him for any plumbing work that needs to be done.
Thanks Ricky for all of your input.
★★★★★
Jake was on time and very good about looking at my furnace. I appreciate all his help. I reccomend him and mainstream electric very highly. thank you Sharon Scott
Maintenance Membership
Join the Care Club
Total home service care, on a schedule.
Members get priority scheduling, seasonal HVAC tune-ups, an annual plumbing & electrical safety inspection, and exclusive discounts — for less than the cost of a single emergency call.
- Priority scheduling
- Seasonal HVAC tune-ups
- Annual safety inspection
- Exclusive member discounts
- Free dispatch on repairs
- No long-term contracts
Pressure & Backflow — Frequently Asked Questions
Do I really need an annual backflow test?
If your water utility sent you a notice, yes — it’s required by code. Backflow assemblies on irrigation systems, fire-suppression sprinklers, and certain commercial accounts must be tested annually by a certified tester and filed with the utility. We handle the test, the paperwork, and any repairs.
What's normal water pressure?
40–80 PSI is the residential standard. Above 80 PSI shortens the life of water heaters, dishwashers, and washing machines. Below 40 PSI feels weak at showers and faucets. We measure at multiple points and recommend PRV adjustment or replacement when needed.
What's a PRV?
A pressure-reduction valve. It sits on the main water line where it enters your home and steps high municipal pressure down to a safe residential level. Most failures show up as water hammer, fluctuating pressure, or a slow drop in shower performance. Diagnosis and rebuild/replacement is usually under an hour.
What's a PVB?
A pressure vacuum breaker — a type of backflow preventer most commonly installed on outdoor irrigation systems. It prevents lawn chemicals and fertilizers from siphoning back into your drinking water if pressure drops. Required by most water utilities and must be tested annually.
How long does service take?
Annual backflow tests are typically 30–45 minutes. PRV replacement is usually 1–2 hours. Larger water-pressure diagnostics with multiple test points can take 2–3 hours. We confirm scope and time when we quote.
Is the work warrantied?
Every repair includes a 1-year Mainstream labor warranty plus the manufacturer warranty on parts. Backflow assembly testing is certified for one year per utility requirement.
*Offers cannot be combined with other promotions or applied to dispatch fees. No cash value. Must present offer at time of service. Call for details.
