ADU & New Construction PlumbingADU plumbing that passes inspection the first time.
We plumb 5+ ADUs every month across Orange County, LA, San Diego County and the Inland Empire, with a 100% inspection pass rate. From underground to final, one licensed crew handles all of it.
Everything your ADU needs, from dirt to final
One crew, one flat bid, and one point of contact for every plumbing phase of your ADU or new build.
Plan review
We review your drawings up front, confirm tie-in points and line sizing, and flag issues before they cost you time in the field.
Underground & sewer
Building drains, sewer lateral tie-ins, and cleanouts, set to grade and ready for underground inspection.
Water service & supply
New water lines from the main house or meter in PEX or copper, sized for your fixture count.
Gas lines
Gas piping for ranges, dryers, and water heaters, sized and pressure-tested to code.
Rough-in & top-out
Drain, waste, vent, and supply lines installed before walls close, coordinated with your framing crew.
Water heater, trim & final
Tank or tankless water heater, fixtures, and trim-out, then final inspection sign-off.
Our process keeps your build on schedule
A 100% inspection pass rate isn't luck. It comes from doing things the same careful way on every job.
Plans & flat bid
We review your drawings, walk the site if needed, and give you a flat-rate bid with no hourly surprises.
Underground
Sewer and water lines trenched, set, and tested, then ready for the underground inspection.
Rough-in & top-out
DWV, supply, and gas lines installed on your framing schedule, usually in 2–5 days.
Pre-inspection check
We pressure-test and walk every line ourselves before the inspector shows up. That's why we pass the first time.
Trim & water heater
Fixtures, water heater, and finish work installed once drywall and cabinets are in.
Final sign-off
We make sure final inspection passes and hand off a finished, working system.
A plumbing sub that keeps your build on schedule
Your schedule depends on every trade showing up, finishing, and passing. We plan around your crew and make sure plumbing never holds up an inspection.
On your framing schedule
Rough-in usually takes 2–5 days, scheduled around your framing crew and inspection dates.
Inspections that pass
We pressure-test and walk every line before the inspector arrives. 100% pass rate, no lost days to re-inspections.
One crew, dirt to final
Underground, water, gas, rough-in, top-out, water heater and trim, all handled by the same licensed crew.
Flat bids you can budget
We review your plans up front and give you one flat-rate bid. No hourly surprises.
Several sites at once
We plumb 5+ ADUs a month, so running multiple builds in parallel is normal for us.
Owners who pick up
You talk directly to Jose or Adann, not a dispatcher. Call or text anytime.
“I had Hydro Plumbers handle the rough and finish plumbing for my ADU, and I couldn’t be happier with their work. The team was friendly, communicative, and worked very quickly without sacrificing the quality of the work. They were also very reasonable with their pricing, which is hard to find these days.”
5.0 from 13 Google reviews · Read them all
Photos: ADU rough-in by our crew.
A plumbing partner builders can count on
General contractors & ADU builders
Reliable scheduling, clean work, and inspections that pass, so your next trade can start on time. Running several ADUs at once? We can handle all of them.
Homeowners
Building an ADU for family or rental income? We'll explain every step in plain English and coordinate with your builder or designer.
Developers & investors
Multi-unit and new construction plumbing with flat pricing you can put in a budget, and owners who pick up the phone.
ADU plumbing across Southern California
For ADUs and new construction, we travel. Our repair and service work stays in Orange County and LA County.
Orange County
Garden Grove, Anaheim, Santa Ana, Huntington Beach, Irvine, Fullerton, Costa Mesa, Orange, Westminster, and more.
Los Angeles County
Long Beach, Lakewood, Cerritos, Downey, Whittier, Norwalk, Bellflower, and more.
San Diego County
ADU and new construction plumbing throughout San Diego County.
Inland Empire
ADU and new construction plumbing across Riverside and San Bernardino counties.
The ADU Plumbing Checklist
10 things to sort out before you break ground, so plumbing doesn't stall your build or blow your budget.
- Can the ADU share the main house's water and sewer?
- Camera-inspect the existing sewer line
- Make sure the ADU can drain by gravity
- Check your water service can handle more fixtures
- Decide on gas or all-electric early
- Pick the water heater before plans are final
- Group the kitchen, bath and laundry together
- Plan the trench route and call 811
- Map out the inspections
- Get a flat bid with a clear scope
Building an ADU? Let's look at your plans.
Free flat-rate bid. Owner-operated. 100% inspection pass rate.
Common questions about ADU plumbing
How much does ADU plumbing cost?
It depends on the ADU's size, number of bathrooms, distance to the main house's water and sewer lines, and whether you need a gas line or a sewer upgrade. We review your plans and give you a free, flat-rate bid, so the number we quote is the number you pay.
Can an ADU share the main house's water and sewer lines?
Often, yes. Whether you can tie into existing lines depends on your city's requirements, the size of the existing lines, fixture count, and how far the ADU is from the house. We check this during plan review so there are no surprises once the trenches are open.
How long does ADU rough-in plumbing take?
Rough-in for a typical ADU usually takes 2–5 days, depending on the number of bathrooms and whether gas lines are involved. We schedule around your framing crew and inspection dates to keep the build moving.
What is your inspection pass rate?
100%. Every plumbing inspection on our ADU and new construction projects has passed. We pressure-test and walk every system before the inspector arrives, so your project doesn't lose days to re-inspections.
Do you work with general contractors and ADU builders?
Yes. We regularly work alongside general contractors, ADU builders, and developers. We also work directly with homeowners who are managing their own build.
Do you serve San Diego and the Inland Empire?
Yes. For ADUs and new construction we serve Orange County, Los Angeles County, San Diego County, and the Inland Empire (Riverside and San Bernardino counties). Our repair and service work stays closer to home in Orange County and LA County.