What HP pump needed for 12,000 s.f. lawn sprinkler system?

[HoneyDo]

Hi. A totally do-it-yourselfer here. Planning a sprinkler system install. Running from a well. Need to know if a 1 1/2 HP pump is enough or if 2HP is overkill. We have no idea how deep the well is. The house used to run off well-water. Currently there's a 1 1/4" line from 2" well/head to 1 HP Flotec pump. We're running a new 2" intake from the well. There's never been a sprinkler system here. Husband is very skilled in his profession (Electrical Contractor) and has done/can do most everything he's attempted. We have a water-guy charging $100 to draw up the plan from the scale-model we gave of the house/lawn. He said "must know GPM and it must be a minimum of 30." Right now we are getting 21 GPM. Need to water approx. 12,000 s.f. Will a 1 1/2 HP pump (new Wayne WLS150) be enough and give us the 30 GPM that the guy charging us $100 says we need? Will 2HP be too much? Please advise.

 

[waterwelldude]

You can water that lawn with just 10gpm.
Whoever designs the sprinkler system should take whatever the pump puts out and build the zones from that.
The more water that is suppled, the fewer zones you need.
The pump you have is fine.

 

[LiQuId]

pumps arnt sized by Hp, they are sized by feet of head discharge and Gpm.

bad idea to pump out of the well, use a holding tank thatr stores the water from the well, that way you dont pump the well dry, thus kiling your aquafer.

the 21 Gpm you are getting, is it a constant 21 gpm ? or do you have a storage tank for high demand times?

..don't pay for the draw-up... waste of money. you should obtain information about the WELL first as you cannot pump more than the well will supply.

 

[speedbump]

I answered this on another Forum. Sounds like your getting the same advice here for the most part. Build the system to the wells ability to supply water.

I was also going to mention that your choice in pump brands is not the best. Flotec and Wayne are among the worst of the bunch. Buying quality instead of price will benefit you greatly down the road. Life expectancy of a Flotec is 1.5 years. A quality pump which won't cost that much more will last 20 years.