UPDATE:  ISO’s countrywide forms filing HO-2021-OFR21 amends the “lawn mower exclusion” so that there is coverage for “A riding lawn mower that, at the time of the ‘occurrence’, is being used to mow a lawn….” This change is effective in most states in March 2022.


Recently Insurance Journal reported a John Hopkins study on lawnmower injuries over an 8-year period at a 6,400 injuries a year incidence rate, with the average cost of those requiring medical attention being $37,000. Needless to say, lawnmowers can be extremely dangerous, raising the question of whether or not a homeowners policy would cover liability claims arising from the ownership, maintenance, or use of a lawnmower.

About 10 years ago, my next-door neighbor was mowing his yard on his riding lawnmower when he ran over a screwdriver he said one of his kids must have left in the yard. The blade stripped the plastic handle off and the steel shaft of the screwdriver ended up imbedded in a tree within 10 ft. of where my son shot basketball in our backyard. So if, for example, a neighbor is injured by a homeowner’s use of a riding lawn mower, would the operator likely have coverage under a homeowners policy? Of course, the answer is “Maybe.”

Despite the perception drilled into the public by incessant price-focused insurance advertising, auto and home insurance is NOT a commodity where coverages are the same. Even when examining industry-standard insurance policies like the ISO HO-3 form, the differences in coverage can be dramatic under different edition dates of policy forms.

For example, the following are excerpts from the “motor vehicle” exclusion in the most recent three editions of the ISO HO-3. One thing to note is that the consensus opinion is that “vehicles” refers to motorized equipment that can transport people or property. In other words, the exclusions below apply to RIDING mowers, not push mowers. The ISO HO-3 in each edition excludes motor vehicles used as follows:

  • 1991 ISO HO-3
    “Used to service an ‘insured’s’ residence”
  • 2000 ISO HO-3
    “Used solely to service an ‘insured’s’ residence”
  • 2011 ISO HO-3
    “Used solely to service a residence”

Consider my next-door neighbor screwdriver example. In the 1991 form, as long as he uses the mower to service his residence at some time, he has liability coverage. As we’ll see, the 1991 ISO form provides the broadest coverage for the use of riding lawnmowers.

However, let’s say he has the 2000 edition of the ISO form. Now he has liability coverage only if the lawnmower is used SOLELY to service his residence. What if he uses his lawn mower to mow the lawn of the church right behind our street that he was a member of? Or what if he uses his mower to mow the yard of another neighbor who is ill? Even worse, what if he is mowing the strip of grass between our two driveways in which our property line runs? If he mows that entire strip of grass, is he no longer SOLELY servicing HIS residence since he’s mowing MY residence’s lawn? A literal interpretation of this language would preclude any future coverage once he uses the auto to service anything other than his own residence…and that lack of coverage would even extend to the use of the mower on his own property.

When ISO made this change in policy language in 2000, the Big “I” Technical Affairs Committee, which meets with ISO annually to suggest form changes, asked ISO to return to the 1991 language due to the onerous nature of the new language. ISO elected not to do this, but they did mitigate the exclusion with the language introduced in the 2011 form edition.

The 2011 form covers the use of a riding mower as long as it is used solely to service “a” residence, not just the insured’s residence. So, in the case of my neighbor mowing that grassy strip between our driveways or mowing a sick neighbor’s yard, he would continue to have coverage. But not if he mows the church property directly behind his home. Unless…let’s say the church property has a parsonage, a residence for the pastor. If he mows the parsonage yard only, he still has coverage, but coverage vanishes FOREVER once he mows the non-residence part of the church property.

In each form edition, the exclusion applies to motor vehicles used in some way to service a residence. What happens if the owner uses the mower off a residence premises BUT then buys a new mower to replace that one. Since the new mower has never been used to service a premises that is not a residence, is coverage now reinstated for that new mower?

To continue the bizarre exposures this language presents. What if my neighbor’s lawn mower breaks down and he borrows my mower to finish mowing his lawn? The blade comes loose, injuring another neighbor who then sues both of us. For the 1991 policy, we should both have coverage under our respective ISO HO-3’s.

However, if we have the 2000 edition, neither of us have coverage. Under the neighbor’s 2000 policy, MY mower has not been used solely to service his residence. In addition, since I’ve loaned my neighbor my mower to service his residence, liability coverage under my own policy vanishes because the mower has no longer been used to solely service my residence.

What if we each have the 2011 edition? It depends. It depends on whether MY mower has ever been used to service a nonresidence premises. Perhaps it never has, but while my neighbor has my mower, he mows a strip of church property that abuts his backyard. Now, coverage vanishes forever if we read this policy language literally.

Keep in mind that we’re only talking about ISO forms with slight language changes between form editions. If it’s a non-ISO policy, even stranger things are possible.

Could you explain this to a customer? Does this really make any sense given the risk presented by riding lawnmowers and the millions of homeowners who use them?

If this single example doesn’t convince you that homeowners insurance is NOT a commodity, I don’t know what would. Caveat emptor.

Photo by Marc van der Chijs

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Bill Wilson

Founder at InsuranceCommentary.com
One of the premier insurance educators in America on form, coverage, and technical issues; Founder and director of the Big “I” Virtual University; Retired Assoc. VP of Education and Research from Independent Insurance Agents & Brokers of America. Reprint Request Information