How Sump Pumps Work In Homes

A sump pump is a requirement if you have a full basement. Without one, your basement can take on water during wet weather events.

Don’t confuse a SUMP PUMP with a SUMP PIT. A sump pit is used to collect the rain water that can form around your home or structure. A sump pump is used to discharge that water away.

How does water enter a sump pit so the pump has a chance to work? Water will take the path of least resistance. The most common way is when the ground water table beneath your home rises and eventually pushes “upwards” beneath the home. (see drawing)

As rains continue, the ground becomes so saturated that it forms a water table.  The ground becomes so saturated, that this water table rises upward and possibly towards the bottom of your basement floor slab.  If the water table rises to the same level as your basement floor, you can experience a wet basement.  This is unless you have a sump pit to collect this water and a sump pump to get it far away from your house.

A home with an average size basement (about 1,400 s.f.) will need 1 sump pump that has the capacity to pump 2,000 gallons of water per hour.  This is an average that works on most homes, but there are always factors that can change this.    If your home is in an extremely wet area, low lying area, near a water source, etc… you may need an additional sump pump or a larger one.

Your sump pit basin should hold at least 30 gallons of water, and be at least 24″ deep.  If your sump pit is too small, or less than 30 gallons, it may cause your sump pump to cycle more often in order to keep up with the water that comes in.   This increased cycling can reduce your sump pumps life span.  A sump pit that is not deep enough will allow the water table to get close to the same level as your basement floor before the sump pump can operate.

The  best way to keep water away from your floor slab, and even needing the sump pump to work is proper drainage around the home.  A good slope of 1″ – 2″ per 5′ is a good minimum to keep any moisture from sinking down around your foundation.  The moisture that comes down on your roof should be directed into your gutters and taken at least 10′ away from the home.

A sump pump should last at least 5 years. They are like a coffee pot or hair dryer.  You never know when it will burn up.  Some people opt to install a 2nd sump pump, directly on top of the primary pump just in case the 1st one decides to call it quits.  This is a good insurance policy, especially if you live in a home that needs the sump pump to work in order to maintain a dry basement.  You may not have time to replace it before your basement floods!   Also, the cost to install a sump pump on an emergency basis can be way more costly.

The sump pump should discharge the water so it gets at least 10′ away from the house.  You don’t want your sump pump to pump the same water over and over again.  It is a common practice to bury the sump pump discharge line under the ground to a nice place in the yard that is far away from the house and has good slope.

The sump pit should be cleaned out at least once per year as debris, silt, etc… can infiltrate it and potentially cause the pump to clog.  Your sump pit and sump pump should be maintained just like  your heating and cooling system.   Annual inspections should be made by someone who knows what they are looking for to help ensure that your sump pump will be ready when it is needed.