Interior plumbing coverage is solid in comprehensive plans. The major exclusion that surprises homeowners: exterior service lines (water main from the street, sewer lateral) are not covered by any standard home warranty. Average exterior line failure costs $4,000–$8,000.
What Plumbing Coverage Typically Includes
What's Excluded
Exterior supply and sewer lines
The pipe from the street to your home - exterior water main, sewer lateral - is NOT covered by standard home warranties. Average exterior line failure: $4,000–$8,000.
Permit and code upgrades
When a pipe repair triggers local code requirements, the warranty covers the repair, not the code compliance upgrade.
Polybutylene and deteriorated galvanized pipe
Many companies exclude repairs when the home has polybutylene (gray plastic, 1978–1995) or severely deteriorated galvanized steel pipes.
Cosmetic damage
Staining, wall damage from a leak, flooring damage - not covered by the home warranty. That falls to homeowners insurance.
Hose bibs
Outside spigots and hose connections are excluded on most plans.
Sprinkler systems
In-ground irrigation systems are not covered (some add-ons exist).
Secondary/consequential damage
Water damage to walls, floors, or belongings from a covered plumbing failure is homeowners insurance territory - not the home warranty.
The Exterior Line Gap - Fill It Separately
The exterior water main and sewer lateral are HomeServe's specialty. If you want coverage for the pipe from the street to your home, HomeServe offers exterior line protection as a separate product. Average exterior sewer line failure: $4,000–$8,000 - worth separate coverage.
Coverage Limits by Company
Most companies cover plumbing with caps in the $500–$3,000 range per claim. Some have annual plumbing limits.
Practical Tips
Water heaters: Water heaters are typically covered separately from plumbing. The connection lines to the water heater are usually covered under general plumbing. See water heater coverage for specifics.