1carwash1
Member
First off, the supply line feeding the pumps appears too small. Secondly, I had the exact same symptom develop at one of my washes. It eventually turned out to be a galvanized nipple corroded on the inside surface thereby reducing the flow of water. As it turns out we replaced our tanks about a year earlier and used a galvanized nipple to transition from female threads to rubber tubing. Over time the nipple corroded and restricted the water flow; causing the same problem you described. We replaced the nipple with PVC and the problem was solved. The old nipple appeared perfect on the outside but was more than 50% restricted on the inside.