I don't see how you can get anything from THEIR insurance company. Since you are not their customer, I would be surprised if they even talked to you. You will need to submit the claim (however high the bill was, all of it was your expense) on your homeowners insurance and then let professionals at your insurance company recover whatever costs they can from your utility, which (if successful) will then subsequently go on THEIR business insurance.
Even though there is nothing wrong with your logic, nobody ever parts with their money unless absolutely necessary, least of all public utilities, some of which have 100+ years of experience dealing with issues like yours. Depending on how high your deductible is, it may not even be worth submitting a claim, but you are the only one who can judge if it's worth it.
New here, trying to get some advice from experts or those who had similar experience before. Long story short. Home water pipe leaking, plumber came, simple fix, but took much longer than expected (two hours weekend rate) because the water pressure was so high that he had to fix it several times, therefore, the total bill is much bigger due to the long labor cost. Talked to local utility, they came in, agreed the pressure was higher than normal and put in a pressure valve on their own budget. My question is that because the higher bill was due to the high water pressure, which should be the local utility company's responsibility, should they reimburse the partial cost of the original plumbing bill? (the unexpected portion) They referred to their insurance company. They said since there was no negligence by the utility company, they can't do anything. I'd say the high water pressure is not their negligence, but it is their responsibility to maintain the normal pressure, therefore, they should undertake the consequence? Anything wrong with my logic? Does it have to the negligence that leads to the reimbursement? Thank you for your advice.
If you think you have a legitmate claim, you will need to bring civil action against them in court. Talk with an attorney . I don't know how much your bill was, but the expense, time and effort probably would exceed a couple of extra hours of a plumbers time. Your insurance likely wouldn't cover it anyway. It would likely be considered a repair or maintenance item.