Repiping a Manufactured Home in San Juan Capistrano: Polybutylene, Underfloor Access and Park Rules
San Juan Capistrano has several manufactured home communities, and many older units still have gray polybutylene or aging supply lines under the floor. How a repipe…
San Juan Capistrano is known for the Mission, Los Rios and horse properties along the creek, but it is also home to a number of manufactured home communities. Many of those homes were set in the 1970s, 80s and 90s, and a good share of them were plumbed with gray polybutylene pipe or early plastic lines that are now reaching the end of their useful life. Repiping a manufactured home is very doable. It just works a little differently from a site-built house.
Why older manufactured homes need attention
- Polybutylene. Common in homes from the late 1970s into the mid 1990s, this gray pipe can become brittle and fail without warning, often at fittings.
- Exposure under the floor. Supply lines run in the underbelly, where rodents, moisture and damaged skirting take a toll.
- Small-diameter lines. Original systems were often minimal, so adding a second bathroom fixture or a washer can drop pressure.
- Patchwork repairs. Decades of spot fixes leave a mix of materials and fittings.
How a manufactured home repipe is done
Most of the work happens from underneath. We open the bottom board (the protective barrier under the floor) in sections, remove the old supply lines, and run new PEX-A with expansion fittings to each fixture. PEX-A flexes enough to snake through tight framing with fewer joints. Lines are supported, insulated where needed, and protected, and the bottom board is sealed back up so it keeps pests and moisture out.
Inside, we replace the shutoff valves and supply connectors at sinks and toilets, and reconnect the water heater, which in many units sits in an exterior closet.
Permits for manufactured homes
Permits work differently here. In mobilehome parks, plumbing permits are typically issued through the California Department of Housing and Community Development (HCD) rather than the city, unless a local agency has taken over that responsibility. Homes on private land may fall under the city. We confirm which agency applies before scheduling so inspections go smoothly.
Working with park management
Most communities have rules for contractor access, work hours, parking and how long a home's water can be off. Some require proof of license and insurance in advance. Let your manager know the dates, and we will provide the paperwork they ask for. If the park's main line or meter needs work, that is usually the park's responsibility, and we can coordinate with their maintenance staff.
Questions to ask before you schedule
- Is the gray pipe polybutylene, and does it run through the whole home?
- What condition is the bottom board in, and will any of it need replacing?
- Where is the shutoff between the park supply and your home?
- Does your homeowners insurance have any requirements about the plumbing?
Related reading
Learn more in our guide to polybutylene pipe replacement and the local post on repiping older homes. Neighbors can visit Dana Point, Ladera Ranch and Mission Viejo, or see every area at repipeinc.com.
Living in a manufactured home community?
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Repipe OC, 23821 Hillhurst Drive, Laguna Niguel, CA 92677, (949) 524-2362, CSLB #1087885 C-36.
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Written by Repipe OC · CSLB #1087885 C-36 · 23821 Hillhurst Drive, Laguna Niguel, CA 92677 · (949) 524-2362