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I am a new home owner and do not know what is "typical" for how often a sump pump should run.
The goal is flood prevention and failure preparation. Finding a straight answer is proving annoyingly difficult.

Obviously,

  • it depends on location and
  • it depends on weather conditions

I know that running every minutes is probably too often. Some people claim theirs runs 5 times a day. Mine runs about every 20-45 minutes. That's as much as 72 times per day. I have no reference for how to interpret that information.

  • What is a "safe" operating frequency for a sump pump?
  • How many cycles is a sump pump good for?
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    Are you actually getting enough water that it needs to pump? Reason I ask is that there's a subtle quirk in the install that's sometimes missed, which can cause the pump to run unnecessarily. Apr 1, 2020 at 15:56
  • As I understand it, yes. The water level rises to the point where the mechanism is tripped and the pump runs. Am I answering your question? I'm not sure what's meant by "needs". Apr 1, 2020 at 16:04
  • I am not knowledgeable enough to provide an answer. My personal experience in our current house: our pump runs every minute or so all spring (while snow is melting) and tapers off to never running during the dry part of summer. We got hit by the tail end of a hurricane (very heavy rain) and our pump triggered about every 10 seconds for a few days. So far, no failures in 14 years.
    – Rob
    Apr 1, 2020 at 16:19
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    @LoremIpsum -- you answered my question, and I don't think you have an issue with a 'relief hole' in the piping. (Background here: garagejournal.com/forum/showthread.php?t=103619 ) Having said that, it probably wouldn't hurt to try and drill one if you don't have it already. Apr 1, 2020 at 16:54

2 Answers 2

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Your sump has a meaningful number of gallons it moves when it cycles. Let's say a 55 gallon sump pump has its start and stop switches set pretty well. Every cycle it pumps out 30 gallons of water. You can measure that.

Pop the covers off and watch your sump pump in action.

First, check the check valve

Obviously, out the top of the sump pump, there is a "riser pipe" that takes the water up and away. Most people make the riser pipe pretty big (doesn't hurt, slightly helps) which means the riser pipe contains a fairly significant quantity of water.

If your sump pump's check valve has failed, all the water in the riser pipe will leak back down into the sump, wasting some of its capacity. It may whoosh right back in, or may trickle back over a couple of minutes.

Check valves fail from the crud in the sump contaminating their valve seals. It may take nothing more than a cleaning.

The ideal way of measuring this is turn the pump off, allow the normal amount of time between cycles, and measure how fast (e.g. in inches per minute) the water normally rises in the sump. Then, turn the pump on, let it pump a cycle, and starting the instant it turns off, measure the inches per minute in the next few minutes. If that rate is higher than the normal rate, that indicates back-leakage.

If the check valve is not easily fixed, another strategy is to reduce the amount of water inventory in the pipe, by reducing pipe size. A little pipe reduction means a lot, due to the square-cube law. If someone gratuitously used 2" and 1" would do, that reduces the water inventory in the pipe by 75%!

The filter can also matter; there should be a coarse-matter filter at the bottom of the sump intake to keep the worst crud from coming up the pipe.

A cleanout might also help; let the sump pump run it down, then use a shop-vac in "wet mode" to go after any remaining crud.

Gallons pumped is also a factor

That is where your "high/low" setting comes into play. Typically there is a float rod with two clamps on it: as the rod rises, the clamp pushes the "on" switch. As the road falls, it pushes the "off" switch. Those are adjustable.

You need to watch the action and see that the sump has a respectable working range: that it pumps down to near empty and doesn't come on until near full. But don't let it suck air!

If you want know cubic feet per pass, or gallons per pass, go online to any web calculator that'll let you compute the volume of a cylinder. For the cylinder height, use the difference in water level (high to low). For cylinder diameter, use the width of your sump. Pick one unit and stick with it, e.g. feet for everything. The calculator will give you cubic feet (or whichever unit you used). Then you can use another calc to convert cubic feet to gallons if you want.

If you want to ease the sump pump's task

And you live on property with elevation differences... then you use a French drain or Buckeye drain to lower the water table around your house. If a septic system is involved in any way, this should be given careful engineering review, otherwise you'll accidentally break the septic field and send poorly treated sewage down your French drain!

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The life span of a pump is hard to evaluate, yes constant cycling can shorten the life but it’s usually the float switch that fails. The quality of the pump is a major factor in life span a quality brass housing with sealed bearings is going to outlast a plastic housed pump in most cases but not all. The water being pumped is the next thing is it clear? Dirty or even muddy. Clear water with a normal ph will be the easiest on a pump, with muddy water eroding the impeller and housing. What is the “head” the pump needs to pump, how many feet is the water being raised the higher the head pressure the harder the pump has to work. The size of the sump pit and flow needed to keep the basement dry If you have a 10 gallon pit the pump will cycle more often than a 55 gallon pit even with a small pit if your pump is cycling two often a better choice can be a smaller pump that runs longer (you always want a cycle or on a heavy day the pit will over flow) I know of several homes that have 2 pumps a smaller one for most of the time then a large one for the heavy days with the large pump being set to cycle above the small ones set points so it cycles less often and prevents flooding if the small pump is not keeping up this method extends the pumps life and reduces energy costs in homes that have more than winter high water issues.

So there are many reasons it is hard to find an answer perfect sizing and setup may last ~8-10 years +-. Most pumps last a few years, keeping the pit clean of sediment and adjusting the cycle time with a properly sized pump will give the longest life. This is in my area that when we need them they are used most of the year.

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