Mobile Home Park Plumbing in California: Where the Park’s Responsibility Ends and Yours Begins
Almost every plumbing argument in a California mobile home park comes down to one invisible line. You own the home; you rent the ground it sits on. Somewhere between the park's water main and your kitchen faucet, responsibility changes hands — and where it changes decides whether a repair is a phone call to the manager or a bill you pay. This is consumer information, not legal advice; for a live dispute, a mobilehome legal aid organization or attorney is the right next step.
You are not a tenant, and not quite an ordinary homeowner
An ordinary California rental runs on habitability law — Civil Code section 1941.1 and the repair-and-deduct machinery in our guide to who pays for plumbing repairs in a California rental. That framework assumes the landlord owns the building. In a park you own the building and rent a space, and the relationship falls instead under the Mobilehome Residency Law (Civil Code section 798 and following). So if your water heater dies, no landlord is on the hook — it is your appliance in your house. If the park's water riser is leaking, that is a different conversation. Our renter and landlord plumbing responsibilities guide is background, not the rule that governs you.
Where the line usually falls: lot services
The clearest statement of the split is Title 25 of the California Code of Regulations, section 1102, the rule the state applies when it inspects parks. It makes the park operator responsible for common areas and park-owned electrical, gas and plumbing equipment, and — where the serving utility does not own them — for the lot services: the gas riser, water riser, lot drain inlet and electrical pedestal at each space. It makes the owner of the home responsible for the home, its accessory structures, and the utility connections up to the lot services.
In plain terms: the riser at the edge of your space is the park's, and the connector, shutoff and piping running from it under the skirting into your floor is yours. The sewer main under the park road is the park's; the drain line from your home to the lot drain inlet is yours.
It is a default, not a universal boundary. The Mobilehome Residency Law separately requires your rental agreement to state the park's maintenance duties: under Civil Code section 798.15(d), management must maintain the physical improvements in the common facilities in good working order, with a reasonable period to fix a sudden breakdown — as soon as possible where health or safety is affected, not more than 30 days otherwise absent exigent circumstances. Some agreements go further, and a few older parks own piping most would not. Read the utility and maintenance sections of your agreement and park rules before you argue with anyone.
The four disputes that come up over and over
- A leak between the riser and the home. A failure in the riser or its valve is normally the park's; a failure in the run from riser to home — where most of these leaks are — is normally yours. Leak detection earns its price by settling which side the leak is on before anyone digs.
- A sewer backup. The useful diagnostic is how many homes are affected. Neighbors backing up too, or wastewater surfacing in a common area, points to the park's main; your home only, and the blockage is usually in your own line before the lot drain inlet. See our guide to telling a clogged drain apart from a main sewer line problem — a camera inspection showing the obstruction past your connection point is the most persuasive document you can hand a manager.
- A gas leak at the riser. If you smell gas, leave, then call the utility or 911 from outside — see our gas leak safety guide. The riser is a listed lot service and normally the park's (or the utility's); the connector and piping inside your home are yours, which is why gas line work in a park often involves two parties.
- A water bill that spikes in a submetered park. Rule out a leak on your side first — read your meter and check for a hidden leak. Under a manufactured home a drip runs for months without a visible puddle.
Submetering: what a park may and may not charge
Many parks are master-metered and submeter to each space. Civil Code section 798.41 permits it: unless the rental agreement says otherwise, management may bill separately for gas, electricity, water, sewer, cable and refuse. What it may not do is turn the utility into a profit center. For gas and electricity, Public Utilities Code section 739.5 requires a master-meter customer to charge each user the rate that would apply buying directly from the utility; the park is compensated by a CPUC-approved discount on its own rate, not a markup on you. For water, Civil Code section 798.40 requires management to post the serving utility's current residential rate schedule, show your submeter's opening and closing readings on each bill, and caps the billing fee at the lesser of a set dollar figure (around $4.75, adjusted over time) or 25% of usage billed. Missing readings, no posted schedule, or a fee that dwarfs the water are checkable problems — our guide to water submetering and rental water billing in California covers how these bills are built.
Under the home: a different job
A manufactured home's supply and drain lines run through the enclosed belly beneath the floor, not a basement or open crawl space, so reaching them means pulling skirting, working in low clearance and resealing the underbelly afterward. Leaks stay hidden far longer, and the labor to reach the pipe often exceeds the labor to fix it — our manufactured home plumbing repair guide has the cost ranges, and our mobile home water heater replacement guide covers that swap's HUD-approval quirks.
Research by Gregory Pierce and Silvia R. González at UCLA, published in Environmental Justice in 2017 on water access problems in California's mobile home parks, found park residents disproportionately served by very small water systems — a category associated with more frequent drinking-water violations and less reliable service (study on Google Scholar). If your park runs its own system, aging infrastructure on the park's side is a realistic explanation for recurring problems.
Who is qualified, and which permit
A licensed California plumbing contractor — CSLB classification C-36 — can do essentially all of this work. Permits are where parks diverge: under Health and Safety Code section 18029, alterations to a manufactured home's own plumbing, electrical, mechanical, structural or fire safety systems generally need an application approved by the Department of Housing and Community Development (HCD) rather than the city building department, and Title 25 separately requires a construction permit from the park's enforcement agency for work in a park or on a lot. The split is case-specific — HCD publishes its own city-versus-HCD guidance — so have your contractor confirm which applies before work starts.
If the park will not act
Two systems handle two different problems, and confusing them wastes months.
- Physical health-and-safety defects in the park's systems — a sewer main surfacing, a failed riser, unsafe utility installations — fall under Title 25 and the Mobilehome Parks Act, which HCD enforces by inspection. Its Mobilehome Assistance Center takes complaints, checks jurisdiction and refers those it holds. One wrinkle: under Health and Safety Code section 18300 a city or county may assume enforcement with HCD's approval, making the local agency your inspector. Ask which agency holds your park before filing.
- Rental agreement and Mobilehome Residency Law disputes — what the park must maintain, utility billing, rules enforcement — are civil matters. HCD has stated it lacks authority to enforce the MRL's Civil Code provisions; those are enforced between the parties in court. HCD does run the Mobilehome Residency Law Protection Program, which takes MRL complaints and refers them to nonprofit legal service providers.
Both routes are underused for an obvious reason: people hesitate to antagonize whoever controls the ground under their house. Esther Sullivan's ethnography Manufactured Insecurity: Mobile Home Parks and Americans' Tenuous Right to Place (University of California Press, 2018) documents how owning a home while renting its land shapes residents' willingness to assert rights (book on Google Scholar). A written paper trail is what makes the MRL's retaliation protections usable.
A checklist for the day it happens
- Photograph and date everything — wet ground, meter reading, backed-up fixture, riser. Photos taken before anyone digs decide who pays.
- Report to management in writing, even if you also call: the section 798.15(d) clock runs from notice.
- Read your rental agreement and park rules first, not after the conversation.
- Ask for a diagnostic, not an opinion — a finding that locates the problem relative to the riser or lot drain inlet turns an argument into a fact. And never let sewage or gas wait while you argue (emergency plumbing costs).
Get the diagnosis first
The fastest way out of a park plumbing dispute is rarely a better argument — it is a licensed plumber's written finding about where the problem physically is. Homeowners in park-dense communities like Hemet, Victorville and Palm Springs use Plumber Comparator for exactly that. Describe the job — a mobile home in a park, whether other homes are affected, how the space is skirted — and request a free quote from a plumber who works on manufactured homes regularly.
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