When a Thornton sump pump stops clearing the pit, the culprit is usually a float that will not lift, a check valve that leaks, a power fault or a worn motor. A plumber can test each part and make sure the water leaves the property instead of going into the city sewer. Call the number on this page to be connected with a local plumber in Thornton.

How the visit usually goes
Calling the number puts you in touch with an independent plumber who works in Thornton. Expect a few quick questions first: is water climbing now, is the pit in a basement or crawl space, roughly how old is the pump and is it silent, humming or running nonstop. On site, the plumber normally checks the outlet and breaker, raises the float by hand, watches a full pump-out and listens for water dropping back through the check valve. They will then follow the discharge pipe to where it ends outdoors. If the pump is finished, you can talk through replacement size and whether a backup or alarm is worth adding.
Price factors
- One failed part versus a complete pump
- Submersible versus pedestal style and the pump's capacity
- Access to the basin and condition of the pit liner
- Moving a discharge that ends at the foundation or in a drain
- Battery backup and high-water alarm options
- Permit work if the job modifies plumbing
Thornton specifics
Thornton is one of the faster-growing suburbs north of Denver. Census survey figures put the median home at 1997, with about 22% built before 1980, so most pits you find here were put in by a builder rather than added later. Builder pumps are often basic models that may never have been tested since closing. The older 1950s to 1970s homes in the south part of the city are where you are more likely to find a pump that has been patched over the years.
The City of Thornton maintains the sewer lines, and wastewater is treated at Metro Water Recovery. That system is sized for household wastewater, not groundwater, so a sump hose run into a laundry tub or floor drain should be rerouted outside. For a sewer problem rather than a sump problem, Thornton Utilities Operations takes calls at 720-977-6500. The city requires permits for plumbing modifications through its Building Inspection Division, and the plumber can say whether your work qualifies.
Before the plumber arrives
- Turn off the pump circuit if water is near the outlet
- Clear boxes and storage away from the pit
- Find the pump's label or receipt if you have it
- Note where the discharge pipe leaves the house
- Check that the outdoor end is not buried in snow or ice
Sump Pumps questions in Thornton
Who do I call if water is coming up through a floor drain instead?
Do I need a permit to replace a sump pump?
Why does my sump pump keep running when it hasn't rained?
Does a sump pit need a sealed lid?
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