Utilities are being split evenly amongst all of the tenants in an apartment building (CA)

I recently found out that our apartment's utility company is splitting utilities evenly across each unit, despite size and usage. We had a thought that the utilities weren't accurate and this month we all compared bills and they are coincidentally all the same at $113.76.

Is this legal?

What can/should we do?

One of our neighbor just blasts the air conditioning all day so it is frustrating to know that I am paying for part of that.