ADU & Garage Conversion Plumbing in Paramount, CA
Water · Drain · Sewer · Gas · Fixtures | Rough-In Through Final, Built to Pass Inspection | CSLB #1051553 | Se Habla Español
The backyard is becoming a home, and every fixture in it depends on decisions made before the slab pours: where the water comes from, where the waste goes, whether the gas line can feed another kitchen, and whether the existing sewer lateral can carry a second household. Ser Plumbing handles the complete plumbing story for ADUs and garage conversions, from the camera down the existing lateral to the final fixture set, planned around one organizing principle: pass inspection the first time.
This is owner-operated service-and-repair plumbing applied to small construction, which is exactly what an ADU is: your general contractor or owner-build project gets a licensed plumbing trade that shows up, coordinates, and documents, with a service company’s manners.
verdict
The Problem: Why People Call
Six situations bring people to an ADU plumbing conversation, and each one changes what the first visit looks at.
What’s Covered
Planning and the lateral verdict
Camera inspection and locating of the existing sewer, a capacity verdict on what a second household means for it, and routing plans for water, waste, and gas that the design can build around. Sewer camera inspection →
Water service and supply rough-in
Connection from the existing service or provision for a separate one per your city and utility’s call, full supply rough-in in PEX or copper, and pressure verified so the new unit never showers weakly.
Drain, waste, and vent
Complete DWV rough-in: correct slopes, proper venting, cleanouts where the future will thank us, and slab work handled for conversions where the garage floor hides the routing.
Sewer connection
Tie-in to the existing lateral where the camera approves it, lateral repair or renewal where it does not, and the trenchless conversation when the route argues for it. Trenchless sewer repair →
Gas lines and capacity
Meter-to-ADU lines sized for the real appliance load, kitchen and heating hookups, and the all-electric alternative conversation where the project leans that way. Gas line services →
Water heating and fixtures
Tank or tankless sized for the unit, low-flow fixture sets that clear California’s efficiency rules, and the final fixture installation that turns rough-in into a home. Tankless water heaters →
Full general contracting: we are the plumbing trade on your project, coordinated with your GC or owner-build
Large-scale tract and multi-unit new construction: deliberately not our lane
Design/architecture: we inform the plan, your designer draws it
Pricing
ADU plumbing prices by the project. Here is how the work is structured:
ADU plumbing prices by the project, honestly: a studio conversion above an existing bathroom wall and a detached two-bath unit at the back of a deep lot are different undertakings, and the written proposal maps yours by fixture count, routing, and the permit path. What stays fixed: written numbers before work, phase billing that matches progress, and no change-order surprises.
Financing is available for qualifying projects through our booking platform.
Why Ser Plumbing for ADU Work
Service-company accountability on a construction job
The owner who quotes it runs it, answers for it, and will still be your plumber in year five when the ADU needs a faucet. Tract subs disappear; we are a Paramount shop, minutes away, and still answering in year five.
The lateral question answered first
Camera before commitment, because the buried line’s condition is the single most expensive surprise an ADU can spring. Sewer camera inspection →
Inspection-first planning
Cleanouts, venting, slopes, and testing planned to the inspector’s checklist from day one. Corrections cost calendars; we build to skip them.
The whole trade under one roof
Sewer, gas, water heating, fixtures, and the repair bench behind them all: no third-party bingo when one scope touches another.
Bilingual through the whole build
Multigenerational projects run on family decisions, and those conversations happen comfortably in English or Spanish, with everyone in the loop.
What Customers Around Paramount Say About Our Project Work
The reviews below load directly from our Google Business Profile. Nothing curated, nothing trimmed.
“I trusted him and his employees to work on my plumbing while I was at work, and I wasn’t disappointed. They ran new water lines for a sink and a toilet and a waste pipe for the toilet as well. The work was impeccable. Everything was up to code with a vent pipe and cleanout installed.”
David B. · July 2026 · new bathroom build-out Read this review on Google →“Very professional and responsible. I’ve had the pleasure of working with Ser Plumbing for both personal home issues and at jobsites for my company. I would highly recommend their top quality work and professionalism.”
Raul M. · April 2024 · contractor Read this review on Google →“Great work. On time. Professional, good prices, highly recommendable. I will use him for future and recommend him to friends.”
Jack C. · November 2023 Read this review on Google →More reviews, live from Google. The widget below loads our latest verified Google reviews in real time. Nothing curated, nothing trimmed.
Leave Us a Google Review ↗ADU Plumbing FAQs
Ten straight answers to the questions we hear on the phone every week.
Ask us directly ↗
Can my ADU share the existing sewer line?
Does the ADU need its own water meter?
Sometimes preferred, occasionally required, often optional: the ruling belongs to your city and water utility, and state ADU law shapes what they can ask. We plumb cleanly for whichever answer your project draws.
Gas or all-electric for the new unit?
Both are buildable, and we run the real numbers on each: existing gas capacity and line-extension cost on one side, electrical service and appliance preferences on the other. Multigenerational kitchens often vote gas; simplicity often votes electric; your project decides.
What plumbing inspections will the project face?
Typically, underground (before slab), rough-in (before cover), gas testing, and final. Each is a checkpoint we build toward on purpose, and passing in sequence is the schedule's best friend.
Why do ADU projects fail plumbing inspection?
The classics: missing cleanouts, venting improvisation, slopes that eyeballed instead of measured, and untested gas work. Every one is cheaper to prevent than to correct behind drywall, which is the whole argument for inspection-first planning.
Do ADU fixtures have special requirements?
California's efficiency standards apply: WaterSense-class fixtures and flow limits throughout. The happy news is that modern efficient fixtures are simply good now, and we spec ones tenants and grandparents alike approve of.
ADU Plumbing Across Paramount, Downey, Bellflower, Lakewood, Long Beach & SE LA County
ADU and garage-conversion plumbing from our Paramount shop across Bellflower, Downey, Lynwood, South Gate, Compton, Bell Gardens, Bell, Walnut Park, Santa Fe Springs, Lakewood, Norwalk, Long Beach, Maywood, Artesia, Cerritos, East Rancho Dominguez, and the surrounding communities.
The backyard is becoming a home. Give it plumbing built to pass.
Call (310) 953-3566.
Call (310) 953-3566 ↗