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.

Service AreasLicensed plumbers across Orange County, LA County and beyond.

Based in Garden Grove, Hydro Plumbers serves homeowners, builders and property managers in more than 50 Southern California cities, with ADU and new construction work in San Diego County and the Inland Empire.

Get a Free Bid (714) 782-2514

Get a free quote

Send us the basics and we'll call you to review plans. Flat-rate bid, no surprises.

Where we work

Cities we serve

Don't see your city? Call (714) 782-2514. If you're in Southern California, we likely cover it. Linked cities have their own ADU plumbing page.

Orange County

Garden Grove, Anaheim, Santa Ana, Westminster, Fountain Valley, Huntington Beach, Orange, Tustin, Irvine, Costa Mesa, Fullerton, Buena Park, Cypress, Stanton, Los Alamitos, Seal Beach, Newport Beach, Placentia, Yorba Linda, Brea, La Habra, La Palma, Villa Park, Lake Forest, Mission Viejo

Los Angeles County

Long Beach, Lakewood, Cerritos, Artesia, Norwalk, Downey, Bellflower, La Mirada, Whittier, Hawaiian Gardens, Signal Hill, Paramount, Torrance, Santa Fe Springs, Pico Rivera, Gardena, Carson

San Diego County

San Diego, Chula Vista, Oceanside, Escondido, Carlsbad

Inland Empire

Riverside, Corona, Ontario, Rancho Cucamonga, Fontana

Need a plumber in your city? Let's talk.

Free flat-rate quotes. Owner-operated. Licensed C-36.

Call (714) 782-2514 Request a Bid