What to Look For When Purchasing a Sump Pump

Howard Shachter, vice president of U.S. Waterproofing, has installed sump pumps in tens of thousands of homes. In this article, he explains what factors to take into account when considering the purchase of a new sump pump for your home.

• The main component that separates a good sump pump from a low quality unit is its pumping capacity. This is measured in gallons per hour, which is based on a standard “head.” The “head” is the water pressure that the pump must fight against when pushing water up and out of your basement. The water in the pipe has volume, and therefore weight, that the pump has to overcome to get water out of basement. For example, the common “head” is 10 feet, which is a typically a little more than a basement is underground. The unit must pump a certain amount of gallons of water out per hour considering the 10 feet of water pressure (a 10-foot head) within the discharge pipe or hose. Typically, standard capacity is measured around a 10-foot head. Most houses need to have around a 2500 to 3000 gallons per hour pumping capacity for their primary unit. If you live in a very wet area, you may need something better. They actually make up to even 9600 gallons per hour sump pumps, but those are only used in unusual situations.

• The other thing to consider is the meantime between failure -– that is, the typical lifespan of the sump pump before it starts giving you problems. Manufacturers tend not to publish that information, though you might be able to find out specifics on some consumer protection forums. The typical lifetime of a pump is 7 to 10 years, but again there are always variables. Sump pumps are usually not continuously used, so time between use can vary lifespan. You might live in a situation where it kicks in every time it rains or perhaps the pump will sit for 6 months without turning on, waiting for the right (or wrong) weather conditions that will require its services.

• The next thing to consider is the switch. Sump pumps have a three switch types used to turn them on and off. What they all have in common is that they measure the level of water in the basin (or “sump”) and turn on when the water level gets too high. There is the free floating (also known as tethered) switch, which is essentially a little floating ball that contains mercury and is attached to the main unit through a loose cord. If the ball is low, then the pump is off. But when it rises to a certain level, it pulls a switch and turns the unit on. There are also vertical action floats which are mechanical floats that ride up and down on a track or rod. These are almost the same as the free floating balls, but they have less chance of getting stuck or knotted as a loose float might. The third type of switch is a diaphragm switch which is air pressure operated and those are the most expensive and least reliable. The diaphragm compresses with water, and when it senses that the water level has risen to a certain point due to the air pressure on the diaphragm, the unit switches on. All three are effective. At U.S. Waterproofing, we prefer to use the mechanical float switch as we feel they are least likely to get trapped by other objects that may find their way into the basin and are also reasonably priced.

• With backup sump pumps, besides the variables mentioned above, there is also batteries to consider. We’ve done tests and found that typical batteries will usually last between a day or two depending on the pump and its battery capability. Keep in mind that pumps usually do not run continuously, so the battery gets a rest in between pumping. When the pump is running less frequently, you can last up to a couple of days without power, relying just on your backup unit. If however, your power frequently goes out, then its time to consider buying a gasoline-operated generator. If it takes regularly takes days for your power to be repaired, you won’t just need this for your sump pump, but for all other necessary electrical appliances.