Those municipalities were doing that anyway. Most only own these smaller pieces of equipment for a few years because that's the service life of small 2-stroke engines. Private citizens might jolly one along for a decade with careful maintenance but municipalities absolutely do not bother with that, which is why these come up on GovDeals and Municibid every month. They are doing this right now today and nobody is running around saying "but the taxes...."
There's a 4-pack of gas-powered spray misters up there now if anybody wants a spray mister.
https://municibid.com/Listing/Details/62615334/4-SOLO-452-Spray-Misters-DSS3519 I see this literally every week or two, much more at the end of summer as they clean out their inventory. (Note the manufacturing date from one of the photos - they were only 4 years "old," which means they're being sold 3 years from when they were probably bought.)
If anything, this could end up saving money in the long run. These electric replacements are more expensive and the batteries cost even more. But after that their service lives are measured in decades - you only need to replace the battery every 2-3 years, which gets longer every year as battery tech gets better, and the batteries are cheaper than the gas-powered replacements they already buy today. What's more, they will no longer need to buy 2-stroke oil, spark plugs, air filters, etc. In the long run this will almost certainly save money.
Your taxes will go up because that's the nature of government and taxes. You will not be able to measure the difference THIS measure makes in what you pay.