Okay, I'm listening to what you are saying. Evidently 1.5 gpm is standard for an energy saving showerhead. A normal showerhead is flow restricted to 2.5 gpm. The next time I'm telling someone how to size a tankless, I'll include that information. And I'm all for using less water - but the 1.5 gpm number hasn't commonly been used in sizing. That said, when we are talking a shower with a rain showerhead, it's not going to be less than 2.5. I'm very comfortable with the 5 - 8 gpm number. What I don't know is the water temps in S. Louisiana in the winter. The average is 67... so is 60 a good winter time number? At 60F water inlet, the NRC98 will do 7.5 gpm - which is about right. Kudzu - Regarding "...almost 20 gpm of hot water..." this is an important thing I want to drive home with the OP and anyone else: You cannot look at that "best possible situation" gpm number on a tankless heater and think it will produce that. The only GPM number that's applicable is the amount of GPM it will produce given the temp rise needed to bring the groundwater in your area up to 105 F in the winter. Note: I made a mistake on the temp rise and GPM on my original example. I quoted the numbers for a 60 degree temp rise when it should have been 50 degree temp rise. At that rate a single heater would provide the needed GPM. I have edited the entry to correct it.

It is much easier to buy a new valve, separate it and install the center part which is damaged. There are 4 screws. Don't slam Spa Parts Plus. They are a wholesaler and are dropping the shipment to their customer. That is a lousy way of doing business. In the future, order from a local guy who can get the same part locally or through a distributor such as SPP. That new valve will not run much. Drain the spa, replace it when there is no water gushing all over the place. No glue required.

New faucets are low flow. I think it is max 2.5 gpm flow at 80 psi pressure, or 2.2 gpm at 60 psi. Sometimes the aerator (at the tip of the spout, gives you a nice bubbly flow instead of a hard splashy flow) is designed to restrict the flow. Maybe some faucets have a different design. The low flow requirement is to save energy (heating water), and water treatment capacity (for example, in Portland we are going to have to build a municipal water treatment facility, and the bigger they are, the more they cost) in addition to the source water itself. Like any conservation measure, what makes sense in the bigger picture can be annoying (or not) at the individual level. As a separate issue, if a kitchen faucet has a sprayer on a hose (including a pull out) it will have a backflow preventer. These are so that the faucet can't siphon contaminated water back into the municipal water system. Usually this is a concern with outside hose bibs attached to hoses whose open ends are laying God Knows Where. But I guess a pullout sprayer is in theory a risk too. You can measure the faucet flow by timing how long it takes to deliver 1 gallon into a pot. If it takes X seconds, then divide 60 by X for the gallons per minute. Or, let it fill a pot for 1 minute and measure the result. If the faucet is flowing 2.2 gpm or 2.5 gpm depending on your water pressure (I wouldn't worry about which one, it's not much difference) then the faucet is probably working as it was intended. I don't know what kind of faucet you have. It can possibly be modified to increase the flow, but I doubt the plumber or faucet maker will help you do that. Warranty and maybe permit issues, etc. On the uneven-ness, it is hard to say what to do without seeing how much it is out of level. Maybe post a picture of the level being held on the faucet and the bubble close up? Also, place the level on the vertical part of the spout, that should be an easier place to do an accurate measurement. How much off-center, relative to the windows, is it? That sounds potentially aggravating. Is the sink also off-center? Is the faucet centered on the sink (was it supposed to be)? How are you defining ''center line''.

Plumbers have pressure gauges and should be able to hook them up between the faucet and the shut off valve. I would measure the pressure when the faucet is off. That establishes maximum pressure at the time of test. Then open the faucet and see if the pressure drops. If the pressure stays steady or does not drop much that suggests the faucet has a blockage of some type. Normally the blockage occurs in the screen at the tip of the faucet. It should unscrew and a you can see dirt in the screen when you take it off. I used to build new homes on well systems instead of public water. We always got some dirt in the system when we first started using the water. A faucet will just barely drip and the screen in the air e ator was always the cause. When ever the washing machine starts filling slowly you know to take off the hoses and clean the screens and everything returns to normal. You can also open the valve to the kitchen faucet after attaching a pressure guage to it and fill a bucket with water and see if the pressure reading is similar to when the faucet is on to establish a pattern of what to expect. I would not take at face value you need to replace the water main. Also those pipes are burried low enough to keep from freezing if you live in a cold climate. In florida it is usually 12-18 inches. I would be very surprised if you car can damage that pipe where ever you live. People on farms drive over there pipes with tractors everywhere.