Texas Plumbing Contractor Certificate of Insurance Requirements

A plumbing contractor's Certificate of Insurance is the gate to commercial and production-homebuilder work in Texas. Because water-damage claims surface after the plumber leaves, commercial GCs verify completed-operations coverage on the COI before allowing a plumbing sub to mobilize. Delivering the right endorsements the first time keeps you on the job.

Endorsements a Commercial GC Verifies

• Additional Insured via CG 20 10 (ongoing operations) and CG 20 37 (completed operations)
• Waiver of Subrogation in favor of the GC and owner
• Primary and Non-Contributory wording
• Products and Completed Operations coverage included
• GL limit of $1M/$2M (commercial: $2M/$2M)
• Workers' comp with waiver of subrogation

Why Plumbing Needs CG 20 37

A leak discovered weeks after rough-in is a completed-operations claim. CG 20 37 extends additional-insured status to completed operations so the GC is protected after the plumbing sub leaves. Many Texas commercial contracts now require both CG 20 10 and CG 20 37 — a COI showing only a generic "Additional Insured" is insufficient and will be rejected.

Water-Damage and Mold Coverage on the COI

Verify your own policy supports the COI you are issuing. A plumbing GL with a full mold exclusion or a water-damage sublimit cannot back a COI claiming completed-operations coverage for water-damage claims. Request the endorsement letter confirming mold and water-damage coverage before you request the certificate.

Backflow and Contamination Coverage

If you install or test backflow preventers, contamination claims from a failed preventer can be severe. Verify your policy does not exclude backflow testing, and confirm the COI reflects that coverage. Some carriers exclude backflow work entirely.

Sub COIs for Rough-In Crews

If you run 1099 rough-in crews, the GC may require their COIs naming you additional insured. Track sub expirations and collect renewals before the old certificate lapses. An uninsured rough-in crew mid-project turns a covered exposure into an uninsured one on your GL.