Sump Pump Repair or Replacement in Sandwich, MA

What a sump pump does

A sump pump sits in a pit, called a basin, dug into the lowest part of a basement or crawl space. Groundwater or drain tile water runs into the basin. When the water rises to a set level, a float switch turns the pump on, and the pump pushes the water out through a discharge pipe to somewhere safe outside.

Most pumps are either submersible, sitting in the water, or pedestal types with the motor on a stalk above the pit. Submersible models are quieter and handle more. Pedestal models are often easier to service and can last a long time when the pit is kept clean.

Either way, the pump works only when four things are in order. The basin must be clear, the switch must move freely, the pump must have power and the discharge line must run clear.

Warning signs your pump is failing

Pumps rarely fail without hinting at it. Learn the sounds and habits of your own pump so you notice changes. A pump that has served a decade is working on borrowed time even if it looks fine.

Test it twice a year and before forecast storms. Pour a bucket of water into the basin and watch whether the pump starts, empties the pit and shuts off.

• The pump runs constantly, or turns on and off every few seconds.
• It makes grinding, rattling or humming sounds without moving water.
• It does not start when the pit is full.
• The pump is more than seven to ten years old.
• Rust, mud or debris are visible in the basin.
• The discharge pipe vibrates or the pump shakes when it runs.

The usual causes of failure

The float switch is the most common failure. It can stick against the side of the basin, get snagged on the power cord or wear out inside. A stuck float on keeps the pump running dry and burns it out. A stuck float off lets the basin overflow.

A clogged intake screen or impeller is next. Sand, silt and small stones get pulled in, and the pump strains. A failed check valve is another, since it lets water in the discharge pipe fall back into the pit and makes the pump cycle over and over.

Power failure, frozen discharge lines and plain old age round out the list. Many of these can be fixed. Some are signs the pump has reached the end of its life.

Repair or replace

Fixing a pump makes sense when the problem is a cheap part, such as a float switch or a check valve, and the pump is still fairly young. Replacing makes sense when the motor is worn, the housing is cracked or corroded, or the pump is old and the basement matters to you.

A new pump is often not much more than a series of repairs on an aging one. If a pump has to be pulled twice in two years, the replacement is usually the better value.

Sizing and picking a new pump

Bigger is not always better. An oversize pump short-cycles, which wears out the motor and the switch. A pump that is too small cannot keep up in a storm. A plumber sizes the pump to the basin, the vertical lift to the discharge point and the amount of water you see in wet weather.

Most homes do well with a one-third or one-half horsepower submersible pump. A cast iron body dissipates heat better than plastic, and a vertical float switch fits a narrow basin better than a tethered one.

A properly installed check valve, a discharge line that slopes away from the house and a sealed basin lid will all extend the life of the new pump and cut humidity in the basement.

Battery backup and water-powered backup

Storms that fill basements often knock out power. A pump on household current is no help when the lights are off. A battery backup pump has its own marine-type battery and a separate switch, and kicks in when the main pump fails or loses power.

A good battery backup system runs for hours, not days, so it buys time. Test the battery each year and replace it every few years. Some owners add an alarm that sounds when the water rises too high.

A generator with a transfer switch is another route, especially for homes with other critical loads. A plumber and an electrician can work together to make sure the pump circuit is safe.

Maintenance that keeps it running

Every few months, pull the lid and look in the basin. Remove silt and stones, and check that the float moves freely. Clean the intake screen on pumps that have one.

Check the discharge pipe outside. Make sure the end is clear, that it does not point back at the foundation and that no ice or debris blocks it. In cold weather, a frozen discharge can make the pump run itself to death.

Keep a written record of the install date and any repairs. If you live in Bourne or Barnstable, see our Bourne plumber page and Barnstable plumber page for coverage. For hands-on help, our sump pump service covers repair, swaps and backup systems.

Frequently asked questions