Skip to content
Pikorua Security

Plumbing subcontractors

Plumbing subcontractor COI requirements

Plumbing losses are water losses: a failed fitting above a finished floor, a test plug that lets go over the weekend, a slow leak that becomes a mold claim. Plumbing COIs fail when the policy behind them excludes exactly those outcomes through fungi, continuous damage or pollution wording, or when completed operations status lapses before the first tenant moves in.

Audit 5 COIs freeExplore demo

Plumbing audit

Clearwater Plumbing & Piping Inc.

Cedar Ridge Senior Living

Deficient
CGL policy
GL 4402-7719-06
AM Best
A- VII
Carrier
Tidewater General Insurance Co.
  • DeficientCG 21 67

    Fungi or bacteria exclusion; no CPL policy covering mold.

  • ReviewCG 20 37

    Completed operations AI edition 07 04 does not match CG 20 10 04 13.

  • DeficientManuscript

    Continuous or progressive damage exclusion on the CGL.

14 rules checked, 2 deficient. Scanned Oct 15, 2026, 10:27 AM ET. Notice sent to sub and broker.
of plumbing subcontractor COI packets are deficient on first review
65%
of plumbing subcontractor COI packets are deficient on first review
Pikorua Security 2026 Benchmark
trade rank by defect rate, 6 points below the all-trade average
10 of 14
trade rank by defect rate, 6 points below the all-trade average
Pikorua Security 2026 Benchmark
of subcontractor and vendor COIs contain material coverage deficiencies or missing endorsements on first review
71%
of subcontractor and vendor COIs contain material coverage deficiencies or missing endorsements on first review
AGC Risk Committee Audit
of COIs claiming additional insured status fail to attach the CG 20 37 completed operations endorsement
64%
of COIs claiming additional insured status fail to attach the CG 20 37 completed operations endorsement
IRMI Construction Risk Survey

Typical exhibit

Typical plumbing insurance requirements

The limits Pikorua Security's plumbing rule template starts from. Your subcontract exhibit controls; set it once per project and every plumbing certificate is checked against it.
Rules in template
14
Hazard tier
Significant
Typical insurance requirements for plumbing subcontractors
CoverageTypical limitWhat to check
Commercial general liability (CG 00 01, occurrence)$1,000,000 each occurrence / $2,000,000 general aggregatePer-project aggregate via CG 25 03. Water losses on occupied renovations can consume a shared aggregate fast.
Products-completed operations aggregate$2,000,000Most plumbing claims are post-completion water damage. This is where the money is paid.
Business auto liability$1,000,000 combined single limitService vans and trucks carrying pipe and fixtures; hired and non-owned included.
Umbrella / excess liability$5,000,000 each occurrence and aggregateRaise on high-rise residential, hospitals and labs, where one riser failure can flood many floors.
Workers compensation / employer's liabilityStatutory / $1,000,000 each accident, $1,000,000 disease each employee, $1,000,000 disease policy limitTrench and confined space work on site utilities raises the severity of plumber injuries.
Contractors pollution liability$1,000,000 each condition / $2,000,000 aggregateSewage backups, mold from leaks and Legionella in domestic water systems are pollution claims under many CGL forms.

Endorsement checklist

Forms to see attached, not just checked

A Y in the ADDL INSD column is not an endorsement. Ask for each form below by number and edition, and read the plumbing sub's schedule of forms against it.

Exclusion watchlist

Exclusions that void plumbing coverage

These never appear on an ACORD 25. They sit in the declarations schedule of forms and the endorsement pages, which is where Pikorua Security reads.
  • Red flag

    CG 21 67 Fungi or Bacteria Exclusion

    A slow leak inside a wall becomes a mold claim within weeks. With CG 21 67 attached, the CGL excludes the mold component, which is often the most expensive part of a water loss.

  • Red flag

    Continuous or progressive damage exclusion

    Carrier manuscript wording that excludes damage that began before the policy period or continued across policy periods. Slow plumbing leaks are the textbook example, and this exclusion lets a carrier deny claims that span renewals.

  • Red flag

    Water damage or water intrusion exclusion

    Some carriers exclude water damage outright for residential or mixed-use projects. For a plumbing sub, that removes the core exposure.

  • Red flag

    CG 21 44 Limitation of Coverage to Designated Premises, Project or Operation

    Small plumbing contractors sometimes carry a policy limited to scheduled operations, such as service and repair only. New construction rough-in and trim on your project may sit outside that schedule.

    Read the CG 21 44 guide

Why water losses decide plumbing compliance

A plumbing subcontractor's insurance is tested almost entirely after the work is done. The pipe is tested, the walls close, and the failure comes later as a burst fitting, a cracked cleanout or a pinhole leak that runs for months. That makes three things decisive: completed operations additional insured status (CG 20 37), a products-completed operations aggregate that has not already been eroded, and the absence of exclusions that carve water and mold out of the policy.

Pikorua Security's plumbing template looks past the limits on the ACORD 25 to the schedule of forms on the declarations page, where CG 21 67 and continuous damage wording appear. A plumbing packet with both, and no pollution policy, is flagged deficient even when every limit clears the exhibit.

Sewage, mold and Legionella are pollution claims

Under many CGL forms, sewage is a pollutant. A backup during a tie-in or a cross-connection in a domestic water system can trigger the pollution exclusion even though nobody thinks of a plumber as an environmental contractor. Legionella in hot water systems and mold from leaks follow the same path.

Require contractors pollution liability on any plumbing scope that includes site utilities, sewer tie-ins, domestic water in healthcare or senior living, or renovation inside an occupied building. Ask for the GC and owner to be named as additional insureds on the CPL policy, not just the CGL.

  • Occurrence-based CPL is preferable; if claims-made, check the retroactive date.
  • Confirm the CPL covers mold and Legionella explicitly.
  • Match the CPL completed operations period to your subcontract.

Testing, turnover and renovation work

On renovation projects in occupied buildings, plumbing work happens above tenants and their property. A test failure on a Friday can damage several floors before anyone notices. Make sure the sub's CGL does not limit property damage on existing structures, and require the umbrella to follow form over the CGL without a water damage restriction. Pikorua Security flags renovation projects automatically when the project type is set to occupied renovation, and adds those checks to the plumbing template.

How to verify a plumbing sub's COI

A manual review of one COI and its endorsement packet takes 25 to 40 min (CFMA Time Study). These are the six checks, in the order Pikorua Security runs them.

  1. 1

    Match the named insured to the subcontract

    Compare the named insured on the ACORD 25 with the legal entity that signed the plumbing subcontract, including the LLC or Inc. suffix. A trade name or DBA is not the contracting entity, and additional insured coverage follows the policy's named insured.

  2. 2

    Check limits against your plumbing exhibit

    Confirm commercial general liability of $1,000,000 each occurrence / $2,000,000 general aggregate, an umbrella of $5,000,000 that follows form over CGL, auto and employer's liability, and statutory workers compensation. Then confirm contractors pollution liability is evidenced, because it does not appear on a standard ACORD 25.

  3. 3

    Read the endorsement pages, not the checkboxes

    A Y in the ADDL INSD or SUBR WVD column is not an endorsement. Confirm CG 20 10, CG 20 37, CG 20 01, CG 24 04, WC 00 03 13, CA 20 48 and CG 25 03 are attached as forms, and that the ongoing and completed operations forms share the same edition date.

  4. 4

    Scan the schedule of forms for plumbing exclusions

    Look for CG 21 67 Fungi or Bacteria Exclusion, continuous or progressive damage exclusion, water damage or water intrusion exclusion and CG 21 44 Limitation of Coverage to Designated Premises, Project or Operation. None of these appear on the certificate; they sit in the declarations schedule of forms and the endorsement pages.

  5. 5

    Check carrier ratings and policy dates

    Confirm each carrier is rated A- VII or better by AM Best and that no policy expires before the plumbing scope and its completed operations period are finished. Set renewal reminders at 60, 30, 15 and 0 days.

  6. 6

    Hold payment and site access until resolved

    Keep the plumbing sub's pay applications and jobsite badges on hold until every finding is resolved, then file the verified packet so it is ready if you ever need to tender a claim.

Try it

Is this plumbing COI compliant?

Toggle what Clearwater Plumbing & Piping Inc.'s packet shows. The verdict updates the way Pikorua Security's plumbing template scores it.

What the packet from Clearwater Plumbing & Piping Inc. shows

  • 04 13 or later edition

  • Edition matches CG 20 10

  • With no mold coverage elsewhere. Red flag if present.

  • Covers sewage, mold, Legionella

  • Carrier manuscript wording. Red flag if present.

  • Applies to the GC and owner

Switch on = present in the packet. Switch off = missing.

Deficient: 2 findings

  • CG 21 67 fungi or bacteria exclusion

    Mold from a leak is excluded.

  • Contractors pollution liability evidenced

    Sewage and mold claims have no policy.

Pikorua Security would send a deficiency notice to the sub and its broker citing each item, and hold payment until a corrected endorsement arrives.

Related trades

All 14 trade guides

Questions

Plumbing COI questions

What insurance should a plumbing subcontractor carry?
A typical GC exhibit asks for CGL of $1,000,000 each occurrence and $2,000,000 aggregate with a $2,000,000 products-completed operations aggregate, $1,000,000 auto, a $5,000,000 umbrella, statutory workers compensation with $1,000,000 employer's liability, and contractors pollution liability for sewage, mold and Legionella exposures. Endorsements should include CG 20 10, CG 20 37, CG 20 01 and waivers of subrogation.
Is mold covered under a plumber's general liability policy?
Often not. Many CGL policies carry CG 21 67, the fungi or bacteria exclusion, which removes coverage for mold. Because a slow plumbing leak quickly becomes a mold claim, require a contractors pollution liability policy that explicitly covers mold, with the GC as an additional insured.
Why do GCs need CG 20 37 from plumbing subs?
Because nearly every plumbing loss happens after the work is complete. CG 20 10 on the 04 13 edition covers ongoing operations only. Without CG 20 37, the GC is not an additional insured when a fitting fails after turnover, and the defense falls on the GC's own policy and retention.

14-day free production trial

Check every plumbing sub's endorsements before they mobilize.

Upload your current plumbing certificates. Pikorua Security reads the endorsement pages, applies the plumbing template and shows every hidden gap in 10 minutes.

Start free trialExplore demo