What PSI does everyone run their RO/DI units at? I get 90 coming from my water line, is this too much?
That's a little on the high side but still within specifications for most membranes. I'm jealous. I only have about 30 PSI. The advantages of higher psi are makes water faster, less waste water. No disadvantages that I know of. You should have a valve on your water supply if you have city water that can be adjusted to regulate your water pressure. PSI around 90 can damage household appliances such as ice makers I've heard.
This is the line coming from the laundry room. It is the closest room to where the water come into the house. Since we live in a state owned house I don't now how the water situation is, but I will have my husband Daniel check for a valve.
If you know where the main water line enters the house that's usually where the valve is. It also could be at the meter I guess. In our city it's mandatory to have one.