These 5 COI (Certificate of Insurance) Mistakes Can Cost Plumbers, Electricians and HVAC Contractors Precious Time and Money.

Why COIs Matter More Than Most Contractors Realize

If you work as a plumber, electrician or HVAC pro, you already know this scenario:

You land the job.
You send the COI.
Then the GC kicks it back with notes like:

• “Missing Additional Insured”
• “Needs Primary & Non-Contributory”
• “Limits don’t meet contract requirements”

COIs are often treated like an afterthought, but in reality they’re how general contractors, property managers, and owners verify you’re transferring risk the way the contract requires.

And here’s the part most tradespeople don’t realize:

👉 A COI can be accepted and still be wrong — until a claim happens.

Q: What Are the Most Common COI Mistakes Plumbers and Electricians Make?

1. Missing Additional Insured Endorsements

Most commercial jobs require the GC or owner to be listed as an Additional Insured.

If the endorsement isn’t correct:

• The GC may not be protected
• You could be in breach of contract
• Claims can come back to you

2. No Primary & Non-Contributory Wording

This one shows up constantly on electrical and plumbing contracts.

If your policy doesn’t respond first, the GC’s insurance may deny the claim and push it back on you.

3. Waiver of Subrogation — The Clause Contractors Overlook

Waiver of Subrogation is often listed right next to Primary & Non-Contributory in contracts, but it’s misunderstood.

Here’s what it really means in plain language:

👉 Without a waiver, your insurance company can sue the GC or owner after paying a claim.
👉 With a waiver in place, they agree not to go after them.

GCs require this because they don’t want:

• Your carrier suing them
• Projects tied up in litigation
• Finger-pointing between insurers

If your policy doesn’t include the waiver endorsement:

• The COI may be rejected
• Or worse, the waiver is promised on the COI but not actually enforceable

That’s a major exposure during a claim.

4. Incorrect Business or Insured Name

If your contract name doesn’t match your legal insured entity:

• Coverage disputes become much harder
• Claims can be delayed or denied
• Jobs can be held up during audits

5. Limits That Don’t Match the Contract

Many plumbing and electrical jobs require:

• Higher general liability limits
• Umbrella or excess liability
• Specific auto limits for service vehicles

Sending a COI with lower limits can result in:

• Rejected certificates
• Back charges
• Delayed payment

Q: Why Do COI Problems Usually Show Up at the Worst Time?

Because COIs are often:

• Pulled quickly
• Based on old templates
• Issued without reviewing the actual contract

When a claim happens, carriers don’t look at the COI first — they look at:

• The policy
• The endorsements
• The contract language

If those don’t line up, that’s when problems surface.

The Real Risk: COI Errors During a Claim

When a COI doesn’t match the policy:

• GCs may tender the claim back to you
• You may lose contractual protection
• Legal costs increase fast
• Relationships with builders and property managers suffer

For plumbers and electricians working commercial or multi-trade jobs, this can mean six-figure exposure from a paperwork mistake.

How Plumbers and Electricians Can Fix COI Issues Before They Start

A better COI process doesn’t mean more paperwork — it means better review.

Best practices that actually work:

• Share the contract with your insurance advisor before signing
• Confirm endorsements, not just COI wording
• Keep entity names consistent across contracts and policies
• Review COIs quarterly, not just at renewal
• Use a standard checklist for GC insurance requirements

Why This Is Becoming a Bigger Issue Now

COI requirements are getting stricter because:

• Claims are larger
• Litigation is more aggressive
• Owners and GCs are pushing risk downhill
• Insurance carriers are enforcing policy language more tightly

That means sloppy COIs are getting caught more often — and punished more severely.

Building a COI Strategy That Actually Protects You

For plumbers and electricians, a COI should:

• Match your contract requirements
• Reflect how your crews actually work
• Include the correct endorsements
• Protect your business during a claim, not just at bid time

As an insurance advisor focused on plumbing, electrical, and mechanical trades, I help contractors:

• Review COI requirements before contracts are signed
• Fix endorsement gaps
• Build “bid-ready” insurance programs
• Avoid job delays and coverage disputes

Final Thoughts

COIs aren’t just administrative noise — they’re a risk transfer tool.

When done correctly, they:

• Keep projects moving
• Protect relationships with GCs
• Reduce claim headaches
• Prevent uncovered losses

When done poorly, they become a liability.

If you’re not sure whether your COIs actually match your contracts, a quick review can prevent major problems down the road.