After 8 years, can the new apartment management company charge for water when there is no way to meter usage?

I'm unable to answer from the facts you've given. Missing: whether you have a lease, or are on a month to month tenancy. If a lease, the lease governs. If it says water is included in the rental, then they can't suddenly charge any more. But of course, when your current lease term is up, they can insert this charge as a new clause in the lease and you'll have to pay or move. If month to month, they can give you a full month's notice (from before 1st of month to end of month) to affect the next month's rental. The only thing to watch is that they do not apportion $2500 in payments from all tenants when the water bill was only $800. But of course, they don't NEED to hide a rent increase like that. The same rules for upping the rent apply to the above discussion of charging for water.

What you're talking about is a "Ratio Utility Billing System," commonly known as RUBS. Personally, I agree with you that this is unfair and should be illegal. Unfortunately, it is not. So long as the parties AGREE to a RUBS system, and the landlord explains the system by which the bill will be distributed, then a landowner is free to do it. Did your landowner make you sign a new lease (or a separate agreement) wherein you agreed to the RUBS? Did the landowner explain to you how the system will work? If so, then you're probably out of luck. If not, then you MAY not be obligated to pay. Of course, without having read your lease and heard the whole story, I can't give you advice, just my generalized opinion. If you're serious, you should contact a local attorney, rather than relying on anybody's generalized ramblings on the Internet. Certainly, you should speak with an attorney before contemplating NOT paying what your landowner is demanding, as the consequences of that action are dire. I am available. The California Department of Consumer Affairs puts out a terrifically useful booklet which can be found for free at: http://www.dca.ca.gov/publications/landlordbook/index.shtml It may have further answers to your questions. Good Luck!