Sump Pump Operation and Homeowner Inspection Guide

Sump pump
Sump pumps are self-activating electrical pumps that protect homes from  moisture intrusion. They are usually installed below basement or crawlspace  floors to remove rising groundwater and surface runoff before it has a chance to  seep into the home. Accumulated water can cause interior damage and encourage  the growth of mold, mildew, and fungus. Pumps should be maintained and equipped  with all necessary components in order to ensure their reliability.

How a Sump Pump Works

A pit, known as a sump pit or sump trench, can be dug at the lowest part of  the basement floor to capture and contain any flowing water. A sump pump sits at  the bottom of this trench (or beside it) and expels excess water through a  series of interconnected pipes to a suitable discharge location. The pump can  sense water levels through a float that rises and falls with fluctuating water  levels in the trench. The sump pump becomes activated and deactivated based on  the height of the float, providing a simple, automated way to monitor and deal  with variable water levels.

Types of Sump Pumps

  • Pedestal sump pumps sit above the water line beside the sump trench and are  not designed to get wet. Since they are not contained within the sump pit, they  can be accessed easily but are also very noisy. They cost roughly $60 to $200,  which is significantly less than other varieties.
  • Submersible sump pumps rest underwater at the bottom of the sump pit, and  are much quieter than pedestal pumps. Their oil-cooled motors and tight seals  protect against water and dust and afford them a long lifespan. They can cost up  to $600.
  • Water-powered sump pumps are normally used as backups and kick in when the  main pump experiences an electrical or mechanical failure.


  • The pump must be kept clean and free of debris. The inlet screen prevents  the passage of dirt and other solid material from entering the pump, but it can  become overwhelmed. Cleanings should occur often for pumps that run constantly.
  • Homeowners should make sure that the float is not tangled or jammed in one  position. A sump pump with a jammed float is useless because it will  not sense when it should turn on and shut off.
  • The pump can be tested by pouring water into the pit to make sure it becomes  activated and expels the water. The homeowner should seek professional  assistance if the pump does not activate.
  • Maintenance should take place annually, and when the home is sold.
  • When testing the pump, no one should ever reach into the pit. The float can  be reached and manipulated with a household item such as a golf club (with a  rubber handle) or anything else non-conductive that happens to be lying  around.

Homeowners and Home Inspectors should check for the presence of the  following:

  • A GFCI. There is considerable debate among home inspectors concerning  whether or not a sump pump should be connected to a GFCI. It is possible that a  GFCI can prevent electrocution, but it is extremely unlikely that a sump  pump will energize water in the first place. It is much more likely that a  GFCI will trip during safe conditions and deactivate the sump pump when it is  needed. A sump pump is among the most critical of all household appliances, and  its deactivation, especially if the tenants are not home, could allow  catastrophic building damage. Codes recommend that appliances in basements and  crawlspaces be connected to GFCIs to reduce the chance of electrical shock, but  this advice is often ignored due to these concerns over nuisance tripping.
  • An alarm. Sump pumps can burn out, lose power, become clogged or misaligned,  or malfunction in a variety of other ways. It is valuable to have a warning  device installed that will signal water build-up. These alarms can alert  homeowners or neighbors of flooding so that it can be resolved before water  damage occurs. Alarms are especially important in residences that are not  occupied for long periods of time. Inspectors should keep in mind that, while an  alarm can be helpful, it is not a requirement.
  • A check valve. This device is the same diameter as the discharge pipe  into which it fits and is usually a different color. A check valve should be  installed in order to prevent pumped water in the discharge line from  re-entering the sump pit when the device is turned off. Without this valve, the  pump will have to work twice as hard to remove the same column of  water, which causes unnecessary strain to the pump components. A check  valve can also prevent the rare yet disturbing possibility that a discharge line  connected to a stream or pond will back-siphon into the sump pit.
  • A backup power source. Power outages are most likely to happen during  heavy rains and floods, which are situations when the sump pump is most needed.  For this reason, combined with the nuisance-tripping from GFCIs, sump pumps  should have a backup power source to rely on. A pump powered by a battery or the  home’s water pressure can also be installed as a backup. Installation of a  backup power source or backup pump is not a requirement, but can be offered to a  client as a recommendation.
  • That the pit that is large enough for the pump. The sump pit does not need  to be constructed from any particular material, as long as it is solid and  provides permanent support for the pump. It must, however, be large enough to  allow the pump room to work properly. Some homeowners use a 5-gallon bucket as a  sump pit, but this is insufficient. For most homes, the sump pit should be 30″h x30″w. One of the most common reasons why  sump pumps fail is that the float gets jammed between the pump and the pit  because the pit is too cramped.
  • A cover. The sump pit should be covered to prevent water from evaporating  into the home as well as protect the pit from debris and small animals that can cause malfunctions.

Discharge Location

The following is good  general information for homeowners:

  • Water must be discharged at least 20 feet from the building.
  • Water should not drain back into the house! Cycling water will place  unnecessary strain on the pump and can weaken the structure’s foundation.
  • Water should not drain onto a neighbor’s property without their approval.
  • Many jurisdictions do not permit pumped water into public sewer systems.
  • Pumped water should never drain into a residence’s septic system. Especially  during heavy rain, a septic drainfield will become saturated and will struggle  to handle the normal flow of water from the house. Additional water from the  sump pump can damage the septic system.

In summary, sump pumps are used to remove excess water from homes that  would otherwise cause property damage. There are multiple types, but they all  monitor water levels and ensure that they do not rise higher than  predetermined levels. Proper maintenance and inspections will ensure pump  efficiency and prolong their lifespan.