What Is a Sump Pump?
A sump pump is a small pump that sits in a pit at the lowest point of a basement or crawl space and removes water before you end up with a soaked floor.
One quick twist many homeowners miss: HVAC systems can also make water. Your air conditioner and high-efficiency furnace often use a condensate pump to move moisture to a drain safely, a similar idea, different source.
What is a sump pump, and what does it do for a home?
Sump pumps protect against basement flooding by collecting water in a sump pit (also called a sump basin) and pumping it away from the foundation. When groundwater rises from a high water table, or when heavy rain saturates soil, water finds weak spots and pushes toward the basement floor. Even tiny cracks can lead to serious water damage and a flooded basement.
Most sump pump systems work best as part of a bigger drainage system, including gutters, downspouts, French drains, and exterior waterproofing. If you’re planning an install or replacement, we are a good starting point for professional sump pump installation services in the St. Louis region.
Where the water comes from and where it should go
As soil gets saturated, water pressure builds and forces water toward your foundation. A proper sump pump discharge sends water through a discharge line and discharge pipe to a safe spot, often a storm drain or a graded area well away from the house. It should not dump into a sanitary sewer or the home’s sewer system.
How a sump pump works (parts explained in plain English)
Here’s how a sump pump works in real life: water rises in the sump pit, the water level hits a switch, and the motor turns the impeller to pump water up and out. In minutes, it can move many gallons of water, depending on the rating (often listed as gph).
Key parts to know:
- Float switch (or a pressure switch): tells the pump when to start.
- Check valve: keeps water from sliding back down the pipe when the pump stops.
- Housing: cast iron is quiet and tough, stainless steel resists corrosion.
- Water alarm: warns you fast if the water rises too high.
If the pump runs constantly, it can mean high inflow, a stuck switch, or a discharge problem. It can also be a sign of a changed water table.
The start and stop switch: float switch vs pressure switch
A float switch rides up with the water and clicks on at a set height. A pressure switch senses pressure from rising water. Float problems are often sticking or snagging; pressure switch issues can show up as short-cycling. A stuck switch can cause nonstop running or no pumping at all.
Types of sump pumps and backup options (what to pick and why)
The main types of sump pumps are submersible sump pumps and pedestal sump pumps. Submersibles sit in the pit and run quietly. Pedestals keep the motor up high and are easier to service, but can be louder.
Sizing comes down to horsepower, the gph you need, pit size, noise, and how far the discharge pipe runs (long runs and lots of vertical lift need more push). Many setups use primary pumps plus a backup system for storms and outages: a battery backup unit, a dedicated battery backup sump pump, or a water-powered backup that uses municipal water and water pressure as its energy source.
Backup protection for storms and outages
A power outage often hits during heavy rain, right when you need it the most. Battery power and other backup power options add real peace of mind, especially with a water alarm. Water-powered backup can work without batteries, but it depends on city water pressure and local rules.
Teddy – Master Plumber
Reviewed by Teddy, Licensed Master Plumber – 27 Years of Experience
Teddy is a trusted Master Plumber at Superior Service with over 27 years of experience. He takes pride in solving even the most complex plumbing challenges with precision and care. From leaky pipes to major installations, Teddy’s expertise ensures every job is done right the first time.
Contact Superior Service
So, what is a sump pump in one sentence? It’s the system that collects unwanted water at your home’s lowest point and moves it out before it causes basement flooding, odors, and damage (and a sealed lid can also help limit soil gas like radon from entering).
Don’t forget HVAC water, either. Condensate needs to be pumped to a drain safely, just like groundwater does. If you’re in the St. Louis region, a plumber can help with sizing, discharge routing, check valves, alarms, and backup setup. Contact the Superior Service team to get your sump pumps and drains handled right.
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