Customer called in needing leak in bathtub looked at. Upon arrival, customer stated that he already found the issue and got it fixed. Customer mentioned if we can take a look at water pressure and also do his water heater flush. Went ahead and started performing water heater flush under his maintenance agreement. While water heater was being flushed, checked water pressure and water pressure at 60psi. Performed a pressure drop test and water pressure dropped to 40psi. Pressure shouldn’t drop more than 10psi. Informed customer of prv potentially giving out and can attribute to low water pressure. Noticed water heater does not have an expansion tank. Educated customer on expansion tank and how they work. Customer is selling home and is under contract. Informed customer that inspector may flag water heater for not having expansion tank since it’s code to have one on all water heater installs. Customer will call us if they need to have expansion tank installed.