Depends on the pump. Those specs will be on the pump.

Nominal PSI is not really a measure of the pump. It will have a max PSI, but you need to know more about gallons per minute.

Do you mean flow rate determines psi? I thought the other way around, like HP determines psi, and psi determines flow rate. Thanks.

fwiw;
I bought a 1hp shallow well Jet pump from ,forget, lowes or homedepot, my water depth is 10 foot - ulta fine white beach sand down there.

Anyhow, 4 - 4' well points = 44 psi at the pump & used larger pipes and a swing flapper check , removed oem check from the pump to keep pressure loss near ziltch, near one pound anyhow according to spec data and nozzeled 17 gpm. Nozzle em 17.5 and pressure suddenly drops to maybe 35#

HP has nothing to do with flow or psi !!!

When flow increases, pressure decreases and when flow decreases pressure increases . Thats simple.

The horse power required is a matter of the load you are putting on the motor. The load will be determined by the flow you demand and the pressure to overcome losses and provide said flow and the efficiency of the pump at that point. Thats almost simple.

I have been asked "if I replace the 1 hp motor on this pump with a 1 1/2 hp motor, how much more pressure will I get? The answer is none at all! No increase in pressure or flow because you increase the horsepower ( all things equal) . An eletric motor is not an engine. you can keep increasing the horsepower all you want ( if the motor bolts up to the wet end ) but you have 3500 rpm or 1750 rpm. No increase in rpm = no change in pump performance ( for our purposes here ).

You need to know the flow that you require and the pressure required to do the job you want the pump to do. A correctly sized pump and motor will last you 25 to 30 years or more with very little maintenance. Of course maybe the pumps at LOWES or such places are cheap enough to go through a trial and error approach and when it seems as though it is right, replace the pump every 3 or 4 years. Not something I could do.

And we haven't even discussed the purpose of the pump. Household water supply? Landscape irrigation? Both? Other?

Hint = Do not use the same pump for water supply and irrigation.

MChristensen

Just noticed the date of the post. Sorry, the follow up may be far to late to help

To oraclexml,
The reason I recomend against using the same pump for the landscape and the water supply is because you have to size the pump for both uses ( demands )and this WILL provide you with a poor operating pump most of the time that it is running. There are a lot of variables involved and I do not have anywhere near enough information on your system.

As for your sprinkler problem,

I am going to assume that you have a submersible pump in the "Water Well". The information you need from the well drilling company is: How much water and at what pressure can the well pump provide?
If the well pump was sized to provide you with enough water ( without any above ground storage tank ) for all you needs, ie water supply, irrigation, livestock, etc. then I am not going to say that you shouldn't connect the landscape to the same pump. It's the only pump.

How is the pump turned on ( and off ) for the landscape?

You say there is no pressure in the sprinkler system. Is there any water at all?

Is the sprinkler system connected to a tank?

I'm not comming up with anything right now accept for how does the pump operate with the sprinkler system. If it worked before then my guess is there is a problem with the part of the system that energizes the pump when your sprinklers come on.

boosterpumptech