How to Measure Your Sump Pump Strength

Not all sump pumps are created equal.  Some are actually stronger than others.  Pump strength is measured by the amount of water that is can push out of a 1 ½ inch PVC discharge line.

Most pumps have a flow chart indicating the Gallons Per Minute (GPM) with the feet of discharge line.  The length or height of discharge line is called head.  10 feet is the average height of discharge line. Most basements have eight foot ceilings and sump pumps are set into the foundation floor about two feet deep. For example the equation “X gpm at 10’ head” means that X gallons can be pumped out of a discharge line 10 feet tall in 1 minute.   The more gallons pumped per minute, the more powerful the pump.

Some manufacturers try to trick homeowners and contractors alike rating their pumps at 0 head. For example: “2000 gpm at 0 head.”  This sounds impressive but doesn’t mean much in a true life application.  There is hardly a real life situation where you would just plug in the pump and not attach a discharge line.

You also have to watch for sump pumps that have high GPM ratings.  If they are pushing out that much water quickly they may be more likely to quit sooner.

Sump pump strength is also measured by the motor’s horse power. Horse power ratings are just like a car engine. Typically, the more horse power the greater the pumping capacity.   Most pumps come in three sizes: 1/3 hp, ½ hp and 1 hp. There are pumps that are less and more, but for residential or commercial applications there are few situations that you would run into a need for a 2, 3, or 1000 HP motor in a sump pump.

No matter what sump pump you select, the BHA recommends installing a back-up pump system to work if the initial pump dies.  It will also extend the lifespan of your whole waterproofing system if you spread the load over multiple pumps.

Professional basement waterproofing companies all over the world sell multiple versions of battery back-up sump pumps and those are typically the better option available on the market.