How Big Of A Sump Pump Do I Need?

Do you ever think about seeing a flooded basement? Oh no! That is a terrible situation ever. I wish that disaster would never happen with anyone. Your important belongings may damage the rising water. Sometimes it may damage your basement if the water is not removed instantly. To eliminate all these problems, you need a sump pump for your basement.

The sump pump may be unfamiliar for some people. Besides, someone has not any accurate idea about the size and type of sump pump they need. In this article, we will explain what is the sump pump? What is the need for a sump pump? How big of a sump pump do I need? Also, some answers to frequently asked questions. So, let’s get started.

What is a sump pump?

A sump pump is used to move accumulated water from the basement through the discharge pipe to any connected drain or pointed area. Generally, a sump pump restrains the basement to be flooded due to over rainfall, snowstorm or, rising water. It is electrical equipment but, some sump pump has a battery backup to work even in the out of electric service during the storm. There are two basic models of sump pumps available to install. The upright (Pedestal) and the submersible. A submersible pump submerges into the water and, the pedestal pump places outside the pit because if it gets wet, the motor will damage. Choose any model which matches your expectation.

How Big Of A Sump Pump Do I Need

 How does a sump pump work?

You have known a sump pump removes the excess water from the basement to the outside of the home. But some people have a curiosity about how the sump pump works. A hole is incised below the main surface of the basement floor, which is called the pit. The pit is known as a basin. The pump is placed into the pit. The pump is enriched with valves that detect the water level. When the water level reaches a certain point of the pump, it turns on automatically and, the water is pushed up through the discharge pipes and safely away from home. As the water level drops, the float switch will disengage and turn off the pump.

** You must be careful about the pointed area you have set to drain water from the basement. You should set your drainage area at that point, as the water cannot return to your house.

How big of a sump pump do I need?

Now, we have come to the main point of this article, the size of the sump pump you need. An oversize sump pump may damage prematurely for constant cycling. On the other hand, an under-sized sump pump cannot remove all the excess water from your basement. So, you should select a perfect size sump pump to prevent damage to your basement or waste of your money. There are some common factors that you should consider to choose the proper size of your sump pump. Here we go.

Reference Chart:

Head (feet)Flow (GPM)

This reference chart explains how much water a sump pump can pump. GPM is the flow rate of gallons per minute. Head is the vertical distance of piping by where the water flow. When the measurement of the head increases, the pump has to work harder. That’s why the maximum flow rate decreases.

To identify the proper size of the sump pump you need, at first, you have to figure out the flow rate of water into your basement. Test it on a rainy day when you think the water flow may be heavy. When the sump pit or sump tank will start to fill with water, measure how far the water rises in one minute. For an 18-inch basin, 1 inch of water means 1 gallon of water. In a 24-inch basin, 1-inch water means 2 gallons of water. If you have an 18-inch basin, and the water rises 20 inches in a minute, then the flow rate is 20 gallons per minute.  But there must be heavy water rising during heavy rainfall and you will need a higher pumping capacity pump. So, it will better if you multiply the flow rate by 1.5. So, (20*1.5) = 30 gallons per minute would be the safe measurement for you.

Now come to the Head measurement step. If your pump is 2-feet below the basement and there is 6-feet to the ceiling, that means an 8-ft Head. We can also see this in the sump pump sizing chart. If the pump rate is 30 GPM, the Head must be 10-feet. The power rating can be considered as 1/3 HP pumps (Horsepower). This size of 1/3 HP pumps will be perfect for the most average-sized house.

** Friction Head is also an important consideration to find out the perfect sizing. Narrow pipes, elbows, check valves and additional piping will increase the friction. It can require a larger pump. So, call your nearest plumber to get the accurate dynamic Head for your pump.

Credit: AMRE Supply


Do I need two sump pumps?

If your sump pump is powerful enough to remove the excess water, you don’t need two sump pumps altogether. But if your primary sump pump is not enough to clear all the water from the basement sump pit or tank, then you may have to install a second one. Besides, if your primary pump can’t provide backup service in the absence of a power supply, then you should buy a backup pump. Battery backup sump pumps could provide battery backup. Otherwise, you may go on with one sump pump.

How many gallons of water does a sump pump discharge?

The most used 1/3 HP sump pump can discharge almost 1800 gallons of water per hour. So, be careful about the pointed area of your water drainage system.

What type of sump pump is better?

A submersible sump pump is the best choice because it is submerged into the basement basin. So, it lasts longer than the pedestal pump. And it is safe for children because it is placed out of the touch of children.

What is the alternative to a sump pump?

The drainage system of a sump pump is not allowed in all places. There are some alternative ways to remove excess water from your basement. Using a mop and sop up the water, using a hand pump and French drainage system can be the best alternative to a sump pump.

Can you drain your sump pump into the sewer line?

Drain the basement water into the sewer line is not legal in some countries. It doesn’t make any sense to drain clear water with a sewer line where all the sewage water goes through. And that can reduce the water discharge level as well. It can cause widespread flooding.

Throughout this whole article, we can say that measuring the size of a sump pump is not a joke. You must be very careful about the size of the sump pump as well as the drainage system. A perfect size sump pump can save you from extreme damage because of water rising. By reading this article, you will get clear information about how big of a sump pump do you need.