Short answer: yes, you need both. Errors and omissions, or E&O for short, covers claims that your work or advice cost a client money. General liability covers bodily injury and property damage you cause. They do not overlap, and most client contracts for engineering firms require both. Who this is for: Engineering firms carrying only a business owners policy or only general liability.
Same coverage, two names. Some carriers and contracts say errors and omissions and others say professional liability. They are the same policy. This page is written around errors and omissions. Here is the same guide written around professional liability.
The short version
- General liability answers physical harm. Errors and omissions answers financial harm from your work.
- Standard general liability policies contain a professional services exclusion, which is exactly the claim you are worried about.
- A business owners policy does not include errors and omissions, no matter how complete it looks.
- Most client contracts for engineering firms require both lines with limits of at least $1M per claim / $1M aggregate.
- If your certificate shows no errors and omissions line, you are uninsured for your biggest exposure.
The one line difference
General liability covers bodily injury and property damage you cause to other people. Errors and omissions covers financial loss a client suffers because of your work or advice. A single claim can involve both, but neither policy will answer for the other.
| The claim | Which policy responds |
|---|---|
| A client visits your office and trips on a cable | General liability |
| A foundation design based on a soils report that under-reported groundwater | Errors and omissions |
| You spill coffee on a client's laptop at their office | General liability |
| An undersized heating, ventilation, and air conditioning (HVAC) system in a medical office | Errors and omissions |
| A former client says your invoice was wrong and refuses to pay | Usually neither, this is a fee dispute |
Why engineers think they are covered when they are not
Three reasons this comes up constantly:
- A business owners policy feels comprehensive. It is not. It bundles property and general liability and stops there.
- Certificates of insurance list both coverages in the same box, which makes them look interchangeable.
- Carriers use different names for the same thing. Errors and omissions, professional liability, malpractice, and technology errors and Omissions can all be the same coverage part depending on the carrier.
If your certificate shows only commercial general liability and a property line, you do not have errors and omissions, no matter how broad the policy feels.
Where the two policies overlap and argue
The messy claims are the ones with both a bodily injury element and a professional element. For engineering firms the classic version is a survey that placed a property line three feet inside a neighboring parcel. A good broker structures the two policies with the same carrier where possible, or at least aligns the retentions, so the two insurers do not spend six months arguing about who defends you.
Watch for the professional services exclusion on your general liability policy. It is standard, it is broad, and it is what pushes these claims to the errors and Omissions form. Some carriers will endorse a narrow carve back, but never rely on it as your errors and omissions coverage.
What a contract usually requires
When prime design agreements send you insurance requirements, they almost always ask for both. Typical language reads: commercial general liability of $1M per occurrence and $2M aggregate, and errors and omissions or professional liability of $1M per claim / $1M aggregate. If your certificate is missing either one, the contract is not satisfied and work can be held up.
What this looks like in practice
Illustrative example. Numbers are typical of claims we see and are not a promise of how any specific claim would be handled.
The setup: A engineering firm that had a business owners policy from a direct writer and assumed it was fully covered.
The claim: The matter started with an undersized heating, ventilation, and air conditioning system in a medical office. The owner claimed $150,000 to replace equipment and lost tenant revenue.
The cost: $40,000 in defense costs and $128,000 in settlement, $168,000 in total, paid inside the policy limit after the retention.
The lesson: The business owners policy contained a professional services exclusion, so the firm funded defense itself until a professional liability policy was put in place at the next renewal. Buying both from the start would have cost a fraction of that.
Frequently asked questions
Q: Do I need both general liability and errors and omissions?
For almost every engineering firm, yes. They cover different claims and most client contracts require both. Errors and omissions answers the expensive claim, and general liability is usually cheap and often required by a landlord or client anyway.
Q: Is professional liability the same as errors and omissions?
Yes. Professional liability, errors and omissions, malpractice coverage, and in technology work technology professional liability are all names for the same basic coverage. What matters is the wording of the insuring agreement, not the label.
Q: Will general liability ever cover a professional mistake?
Very rarely, and not by design. Standard general liability forms carry a professional services exclusion. If a claim mixes bodily injury with a professional error, the general liability policy may cover the injury piece only.
Q: I work from home and never meet clients. Do I still need general liability?
Often yes, because clients and landlords ask for it and because it is inexpensive. If a client contract requires a certificate, general liability is almost always on the list.
Q: Which one do I buy first if money is tight?
Errors and omissions. It is the policy that answers the claim your business actually creates. General liability can usually be added mid term for a few hundred dollars when a contract demands it.
Q: Does one claim ever hit both policies?
It can. When that happens, both insurers get notice, each defends its own piece, and coordinating them early keeps you out of a coverage fight while you are already dealing with a claim.
How Morrow helps engineering firms
Morrow is a licensed independent commercial insurance brokerage that specializes in engineering firms. Sorting out which policy answers which claim is exactly the kind of question we answer every week, and because we place this coverage every day we know which carriers write it well, which forms are broad, and which contract language actually needs an endorsement behind it.
- We read the contract clause and tell you what your current policy already does and does not do.
- We market your account to carriers that have real appetite for engineering firms rather than whoever answers first.
- We issue certificates the same day a client asks, with the endorsements listed correctly.
- We stay on the file at renewal so limits, retroactive dates, and contract requirements do not quietly drift.
Get in touch and we will see how we can help. Tell us what you do, send over any contract that is driving the requirement, and send us the question and we will tell you where you stand. Start at morrowinsure.com or reach the team through the contact options on that page.
One more thing. This article is general information for engineering firms and is not legal advice, tax advice, or a statement of coverage. Policy wording controls in every case, and forms vary by carrier and by state. Have a licensed advisor review your own policy and your own contract before you rely on any of it.
Last updated: Reviewed by the Morrow commercial lines team. Last updated August 2026.