What Size Sump Pump Do I Need?

When considering the amount of rainfall that reaches a North American house on average during a year, it should come as no surprise that a lot of homeowners choose to install a sump pump pit on their property or already has one. Some homeowners are very fortunate and they never hear their sump pumps work, but those living in regions that don’t drain well, know the importance of one.
Whether you live in a region that drain well or not, it is of great importance to have a sump pump with sufficient power for those times when natural drainage doesn’t cut it.
The explanation below outlines how you can easily calculate the size sump pump needed for your home.
Starting off, you’ll have to wait for a really wet and rainy day. On this day, let your sump pump run until the water recedes to a level of shutoff. Measure how far the water rose after keeping the pump off for one minute.
Typically, a sump pump measures around 18” in diameter. Measure yours to make sure! If this is the case for you, each inch water inside of the pit will amount to about one gallon.
The quantity of inches risen in a one-minute timeframe needs to be multiplied by 60. This calculation will estimate the amount of water that will typically enter your pit when steady rainfall occurs in a one-hour timeframe. This number must then be multiplied by 1.5 (which is known as the safety factor) to configure the pumping power needed.
If your sump pit receives 25” of water within a one-minute timeframe, that would amount to approximately 25 gallons of water. Your calculation would look as follows:
25 gallons of water multiplied by the 60 minute time-frame x 1.5 = 2250 GPH (gallons per hour) pumping power needed.
To maintain your sump pump, you should periodically make sure that it stays in top condition by following these easy steps:
1.       Make sure that the operation of the float’s up-and-down movement is not restricted.
2.       Make sure that water is being discharged by the outdoor end of the discharge pipe when it is running. Discharge of water can be restricted by several things such as a stuck check valve, an impeller being loose on its shaft, or a plugged water pipe.
3.       Make sure that the pump is still operating properly at the beginning of each rainy season. To do this, insert enough water in the sump pump basin to trigger a response in the float switch.
Other things to take into consideration when installing a sump pump in the basin size, the check valve and the electrical circuit.
Basin Size
As illustrated above, the basin size plays a role in how long a sump pump runs and takes to fill up. The standard size for most residences is an 18-inch basin diameter or sump pit.  If your home has an undersized basin that fills up too quickly between pumping cycles, consider installing a wider basin to accommodate the flow.
Alternatively, installing an adjustable float switch which allows the water to rise to a higher-level before the pump is turned on is a cheaper route to follow.
Most pumps also depend on water to lubricate and cool pump seals, so make sure that the float-switch is positioned in such a way that it prevents the pump from running dry. If you need a pump with a float that can be adjusted to different lengths of operation, then a pedestal-type pump is the one to go for.
Check Valve
The check valve is responsible for keeping water in the discharge from flowing back into the basin between pump cycles. Selecting a swing-type valve that is the same size as the discharge pipe is a good option. Installation should be done just above the sump pump.
Electrical Circuit
Each sump pump requires its own motor control circuit and breaker. When installing electrical circuits, be sure to check all applicable local electrical codes and ordinances.

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