With the right discharge line, your pump runs as intended by the manufacturer. Let’s say you needed 1000 gallons of water (for whatever purpose) and a 2” discharge of a portable pump gives you 150 gpm and a garden hose gives you 20gpm (generous).
With the 2” line you run the pump for under 7 minutes to attain the goal.
With the garden hose you run the pump for 50 minutes to attain the goal.
Even if you think “oh I can afford a gallon of fuel easier than $800 worth of poly pipe” consider this…your pump is running out of spec, flat out for an hour at a time.
Using firehouse type line with a fog type nozzle will water that garden like a good rain. Not to mention if you ever had a fire, that volume of water could save everything!
