sfhc, My 2 cents it to get a regulator on your house because your faucets, shower and water appliances are not designed to withstand high pressure over time. Nor is your irrigation system. High pressure systems are prone to water-hammer problems and noisy pipes. You shouldn't be looking for the govt agency to install something a home builder should have done and usually does. The water agency sets its limit very high so it isn't required and doesn't have to pay the cost of giving everyone a house pressure regulator. Normal house pressure should be 45 to 60 psi. If you had your house at 55 psi, your in-line pressure regulators for drip would work. You want a 15-30 psi limit for drip. JMHO Aloha

mac, Do pressure readings at the 400' faucet, at a new faucet or tee at the 700' mark and at the end. Does your pump have a pressure meter at its outlet? This will give you a graph of pressure loss along the length of your pipe. A booster pump making up the pressure loss would be what's needed. Another way would be to run another two inch line along the first and reduce the flow rate of both pipes thus reducing the velocity in the pipes which is what is causing the large pressure loss through internal pipe skin friction. Also check any valves in the system that may be causing a restriction. Valves, tees and bend produce on their own pressure losses. If your pipe is too small for the flow rate you may experience water hammer which cause pipe brakes and fitting failures. First step is checking your pressure loss along the pipe. GL Aloha

DWPC, Each size pressure regulator lists the flow rate for the pressure range drop it produces. If you require a certain flow rate at the downstream side of the regulator look for the size regulator that gives you that flow rate. Your pressure is high so you may need to put two pressure regulators in series to provide two drops to the desired pressure and the demand flow. You can also put the PR in parallel to provide the full drop and get the rated flow from both PRs. Does anyone agrees with this because it is JMHO. Someone may have more detailed info on this. This is a general overview. This info is for a direct-operated PR type. Aloha

Brian, You have laid out all the worries pretty well. The facts are: Pump operating correctly at 50-65 psi. 3 zones with 5 heads each 1" Dia. poly main with 3/4" Dia. laterals to heads. Literature says heads throw is 30 to 50 feet. Actual throw is 15 to 20 feet System is 17 years old. Notice gradual decrease in throw distance over 4 years. Most are original Rainbird heads. More Data needed: 1. Model No.s of heads and type. with that I can research throw distance per psi range for head. 2. Check pressure and flow from Pump or Tank outlet during operating irrigation system. 3. Is pump system separate from the house? 4. What is average level of Calcium and Iron in the water. Was the water in the well tested previous and could it be tested now. 6. Is the coverage still adequate or does the lawn now have dry spots? 7. What is the pumps design pressure and flow? Do you have the design curve literature? If not what is the make model, HP and amp required to operate the pump? I would start by checking from the source to the valves for design pressure and flow. If you had historical data for this you will see the pattern. This is just the beginning of the water audit for your system. Are you in for the long haul? Aloha