Your sump pump is running and it will not shut off. Before you assume the pump is failing, understand that a pump running hard is often doing exactly what it should. On the Front Range, spring snowmelt off the foothills and the high water table under lower-lying neighborhoods can push real water at the pit for weeks, and a healthy pump will cycle a lot during that stretch. The problem is telling the difference between "working hard for a good reason" and "running because something is broken." That is what this page is for. We will walk the three DIY checks that solve most cases in ten minutes, and we will be straight about the two symptoms that mean stop, this is a sizing or failure call.
Why does my sump pump run constantly: the short answer first
A sump pump that runs constantly is doing one of two things: keeping up with real groundwater, or cycling on water that never actually left the pit. On the Front Range, March through May is peak inflow. Snowmelt off Green Mountain and the foothills saturates the expansive clay soil, and that clay holds water against the foundation for days instead of draining it, so the pit refills faster than in a dry month. If your pump runs a lot during snowmelt but the pit level drops each time it fires, that is a working pump under a heavy load. If the level never drops, or the pump kicks on again seconds after it shuts off, something mechanical is wrong. The three usual culprits are a stuck float switch, a failed check valve, and a frozen or clogged discharge line.
Work them in that order. Most of the time you will find the fault yourself.
Sump pump keeps running: the three DIY checks
Before you touch anything, unplug the pump so it cannot cycle on your hand. Then work these three in order.
1. The float switch is stuck. The float is the part that rises with the water and tells the pump to turn on. If it hangs up against the pit wall, the discharge pipe, or a tangle of its own cord, it stays in the "on" position and the pump never stops. Look down into the pit. The float should move up and down freely through its full travel. Free it, re-route the cord so it cannot snag, and confirm the float swings clean. This is the single most common cause of a pump that will not quit. 2. The check valve failed. The check valve is the one-way flap on the discharge pipe, usually a foot or so above the pump. It stops the water in the vertical pipe from draining back into the pit after the pump shuts off. When it fails, that column of water falls straight back down, the pit refills instantly, and the pump fires again. This is short cycling, and it is covered in its own section below because it is the fault people most often misread as a dying pump. 3. The discharge line is frozen or clogged. If the pump runs but the water level never drops, the water has nowhere to go. In Front Range winters the discharge line freezes where it exits the house, especially on a run that does not pitch downhill. In any season it can clog with silt, ice, or a collapsed section. Walk outside and confirm water is actually flowing out the end of the discharge, and that the line terminates at least 10 feet from the foundation on a downhill grade. A discharge that dumps right at the wall just feeds the pit it came from.
If the float swings free, the check valve holds, and the discharge is flowing clear to 10 feet out, but the pump still will not stop, the fault is deeper. That is the point to talk to a licensed tech about your sump system rather than keep guessing. You know the total before we touch anything.
Sump pump short cycling: on, off, on again in seconds
Short cycling is the specific pattern where the pump runs for a few seconds, shuts off, then fires right back up, over and over. It is hard on the motor and it burns out a pump years early. After scoping and servicing pits across the metro, we have learned short cycling almost always traces to one of three things, and only one of them is the pump itself.
> A pump that short cycles is not lazy. It is being told to start and stop faster than any motor is built to handle, and that is what shortens its life.
Here is the honest gate. If you replaced the check valve and the pump still short cycles, or the pit is clearly undersized for the water coming in, that is a sizing and installation call, not a Saturday fix. We size the pump and pit to the actual groundwater load, typically a 1/2 HP or 3/4 HP submersible matched to the basin, and we set the float range so the pump runs a full cycle. Get it right once and the pump lasts the way it should. Call (720) 880-8064 and we will diagnose it before quoting.
When to stop and call instead of fixing it yourself
We mean it when we say handle the float, the check valve, and the discharge yourself if you can. We also mean it when we say some of this is not DIY. Stop and call if any of this is true:
Deft Plumbing is licensed, bonded, and insured in Colorado, rated 5 stars across 37 verified reviews, and we quote a flat rate that covers the pump, the parts, labor, and haul-away before we pick up a wrench. Whether it is a check valve swap or a full primary pump with battery backup, you know the number first. We handle it across the metro, including sump pump service in Arvada and sump pump installation for Aurora basements.
Frequently asked questions
Do I really need a battery backup sump pump in Denver?
Yes, and it is the piece homeowners skip and regret. Colorado's heaviest inflow season is spring snowmelt, roughly March through May, and the storms that drive that water are the same ones that knock out power. A primary pump with no backup fails exactly when it is working hardest. A battery backup unit sits in the same pit, triggers on its own float set an inch or two above the primary, runs off a dedicated battery bank, and keeps pumping through an outage. On the Front Range we treat it as standard, not an add-on. Ask us about it when we spec your system.
How far should a sump pump discharge from the house?
At least 10 feet from the foundation, on a downhill grade, per local grading requirements. A discharge that dumps right at the wall just soaks back into the soil and feeds the same pit it came from, which is a common reason a pump seems to run non-stop. The line should also pitch downward the whole way so it drains fully and does not hold water that can freeze in winter. If your discharge ends short of 10 feet or runs level, that is worth correcting before the next melt season.
Is it bad if my sump pump runs all the time during spring?
Not necessarily. During snowmelt, a healthy pump under a high water table can cycle frequently and still be fine, as long as the pit level drops each time it fires. What is not fine is the pump running while the level stays put, or short cycling on and off every few seconds. Watch the water level for a minute. If it drops with each cycle, the pump is keeping up. If it does not, work the checks above or call (720) 880-8064 and we will sort out whether it is the float, the check valve, the discharge, or a sizing problem.