HOA Board to impose a water usage fee

Probably not unless your HOA documents have language that allows the association to put certain requirements on non-owner occupied units. Read those first (board members like yourself should have more than a passing familiarity with them anyway).

It would appear you're concerned that the units housing more people are using more water, and with one meter, it's hard to gauge if that's true or not. You might want to talk to the water company to see what can be done, as I'm sure they have other customers in the same situation.

I remember from my apartment living days, the gas heat was included in the rent and the complex was in the utility's budget plan, where it paid a set amount each month. At the end of winter, the complex would get a bill from the gas company for the difference, the manager would divide that by the number of apartments and individual tenants would be responsible for his/her/their portion.

That could be one way you can address this, otherwise, you might want to look into giving everyone individual water meters so each owner is responsible for his/her own bill. Of course, this will likely take some construction, which would be expensive - and the association would have to pay for it.

Yes, IF you change the language of your CCRs.

I found a paragraph regarding liens & assessments in our CC&Rs, that seems to cover the water usage assessment.

Reads as follows:

a) The Board of Directors of Association shall have the right from time to time to make
assessments upon any condominium (1) to meet the necessary maintainance, operation, and administrative expenditures of the corporatation and (2) to provide adequate reserves for such expenditures.

Thank you for all your input

Richard makes a good point. Our condos, for instance, have variable assessments based on s.f. for water, gas & bldg. insurance.

Unless each condo unit has its own water meter, or has the capability of being "sub-metered," I think your condo will struggle to prove it is being fair to each condo owner.

A number of companies do sub-metering. Sometimes a condominium community cannot sub-meter individual condos without massive re-piping, tearing out walls and so on.

Is this your HOA? Desperately looking for a culprit?
https://www.expertlaw.com/forums/showthread.php?t=228375

You're setting yourself up for major problems, assuming there are no meters per unit. I've been a little ways down this road and can tell you it's a slippery slope. Just because one household has more people in it does not mean they use more water. You can not prove that without meters. You have 4 family members that shower in under 3 minutes each in one home, and a man and wife that each enjoy 20 minute showers twice a day in the other.

If you need to raise the assessments to cover water usage it will have to be an increase to all units. If you're trying to get at the rentals because they are rentals, then you need to work on your governing documents.

Disregard that last post. With 7 out of 18 rented and the requirement for changing the CC&R's probably being 2/3rds of the owners agreeing, it would never pass.

Not sure how blaming the old lady comes into play
I just wanted to get some friendly advise on this matter from more experienced Board members.
So far the forum has been a great. Its a great opportunity to get someone else's input.
Lets keep it that way

I guess you didn't follow the link. I was wondering if you were a poster on another forum where they had a similar situation, except caused by an old lady. The state, number of units and type of association was the same. If you had read the posts and followed the links, you could have seen that. Lets keep it that way.