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Reason I ask is, we're on our third (fourth if you count the one that was here when we bought the house) in ~12 years now; just had to replace it last night. Probably not a coincidence that pretty much all of them have a 3 year warranty.

I think we narrowly dodged a bullet this time. Two days before the main pump failed, the backup pump alarm went off indicating a problem with the battery. Opened it up, and the water level in the battery was so low that it was well below the tops of the battery plates -- I could not see any liquid at all. WTF -- it is supposed to have an "add water" alarm that goes off before the level gets anywhere near that low. If the two failures had coincided, we could've easily ended up with a flooded basement.

10 years seems to be the accepted answer, though one caveat I found was if you buy cheap don't expect it last if it is running regularly.

Sometimes I'm glad I'm from an area where they don't even need to install the sumps.

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Sounds like you've got something else wrong or your pump is running harder than most areas.

Arvald wrote:

10 years seems to be the accepted answer, though one caveat I found was if you buy cheap don't expect it last if it is running regularly.

I haven't been buying the cheapest ones, nor the most expensive ones. Pretty much the middle of the range.

Arvald wrote:

Sometimes I'm glad I'm from an area where they don't even need to install the sumps.

Yeah, sometimes I find myself wondering whether having the basement is worth dealing with sump pumps and seepage.

superjawes wrote:

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Sounds like you've got something else wrong or your pump is running harder than most areas.

Well, I am starting to suspect that we have some drainage issues, so yeah, the pump may be working a little too hard. I'm also thinking that on the previous one I may have mounted the float switch a little too low, causing the pump to cycle more often than necessary. When I installed the new one last night I moved the switch up about 4 inches from its previous location.

When I lived in KS (ages 0 - 26), we lived in one home for 15 years and another for ten. We had to replace the sump once in the 15 year old house (which we built) and the other house we haven't had to replace the pump since moving in. The house was built in 1991, but I don't know if the previous owner replaced the pump ever.

edit: so yeah, something weird is going on. Must have some pretty bad drainage issues.

My first one died a premature death from a stone that the builder left in the pit after ten years or so (plastic impeller.) My next one (Home Depot) is still going strong after 15. Pedestal type, if that matters. I ran some plastic pipe to divert the water far from the foundation

Our drainage was exremely poor and there was a lot of underground water affecting the neighbors as well when the house was built, I brought in enough topsoil to ensure that water ran away from the foundation, and the underground water is no longer an issue - I assume it eventually percolated away - lots of clay in this area. If it runs a lot, you have a drainage problem and you need to fix it.

Thinking back, one of the pumps may have suffered some unusual wear due to a faulty check valve. The check valve failed, causing all of the water sitting in the discharge pipe to siphon back into the sump at the end of each pumping cycle. This caused the pump to cycle very frequently until we noticed the problem. So there's a plausible explanation for at least one of the early failures.

Hmm... maybe I should move the check valve closer to the pump? There's currently about 7 feet of 1-1/2" pipe between the pump and the check valve (the valve is approximately mid-way between the bottom of the sump and ground level), so there's still some water that drains back into the sump from the riser pipe.

Check valve should sit right at the pump output to minimize flush-back.

Captain Ned wrote:

Check valve should sit right at the pump output to minimize flush-back.

OK, I will need to fix that. The present location of the check valve was not my doing (previous owner). I've just re-used the same plumbing each time the pump failed (and when I replaced the check valve); the only actual modification I've made to the pipes was cutting off the old coupler and putting on a larger one when I switched to a pump with a larger diameter discharge port.

Thinking even further back than the failed check valve incident, there was also an incident where a faulty float switch caused the pump to get stuck "on". The pump housing was very hot when this was discovered. I guess they are designed to be cooled by the water in the sump, so running them continuously after the sump is empty is probably not a good idea? So I guess I may have plausible explanations for two of the three premature pump deaths. Neither of the pumps died then and there, but I could certainly believe that the extra running time and/or frequent cycling shortened their service life.

Most submersible pumps have a duty cycle rating, applicable when they're not fully submerged.

Captain Ned wrote:

Most submersible pumps have a duty cycle rating, applicable when they're not fully submerged.

The low mounted float switch may have factored into this as well, then. I believe the pump was coming on before it was fully submerged. In retrospect, that issue combined with the high location of the check valve sound like a recipe for extra wear and tear on the pump...

Mine sits in a plastic trashcan full of drilled holes dug into the dirt floor cellar. My float switch comes on when there's about 6-8 inches of water above the top of the pump casing and cuts out when the pump is about halfway submerged. Been running the same pump for over a decade. In fact, I've replaced the float switch twice since I bought the pump, and the pump is a simple Home Depot cheapie.

There's actually a flexible rubber coupling in the line a couple of feet above the pump. Swapping that with the check valve should be a no-brainer. I guess I have a little project for this evening now.

As someone mentioned, a check-valve close to the outlet of the pump is usually normal practice for a regular pump, but not really required for a sump pump, since it can drain back into the sump.
Also I don't think I would want all that cruddy water stagnating in the pipes, the solids will settle out and could cause blockage.
Also with a check valve, any water that is left in the pipe that could be exposed to cold weather could freeze and crack your pipe, OR plug it and burn out your pump.
If you want to install a check valve anyway, good piping practice dictates that it should be at least 10 pipe diameters away from the outlet.

Your float switch is very important though, it should be set so there is at least 4 inches of water above the sump intake. This will help prevent vortexing causing the pump to bring in air.

No you didn't mention whether it is the electric motor, impeller or bearings which are failing? Usually a half decent sump pump set up properly should last years.

One thing to look for would be a cast iron impeller, and sealed ball bearing all through the unit. Some electric motors come with sleeves and have to lubricated regularly.

MarkD wrote:

Our drainage was exremely poor and there was a lot of underground water affecting the neighbors as well when the house was built, I brought in enough topsoil to ensure that water ran away from the foundation, and the underground water is no longer an issue

This, if it hasn't already been ruled out and/or repaired. My folks' house experienced 12-18 inches of settling around the south and east foundation walls in 30-odd years due to expansive clay soils, the worst of it occurring during a 5-year drought period. Most of their drainage issues turned out to be caused by water running back toward the foundation, then going straight down to the basement. Building up the soil to form a shallow slope solved most of the problem.

Another source of unexpected water can be old service lines. For years my folks' sump ran 2-3 times a week and it turned out the below-grade soil on the north side of the house (which faces the street) was supersaturated due to problems in the water service. The leaks were on the upstream side of the meter, so there was no obvious source until it got bad enough that the meter pit started retaining several inches of water.

just brew it! wrote:

There's actually a flexible rubber coupling in the line a couple of feet above the pump. Swapping that with the check valve should be a no-brainer. I guess I have a little project for this evening now.

That should do the job. I assume this is pumping into a city sewer line? If so, no worries about freezing or other nasties. Mine, OTOH, pumps out the cellar window and through a long flex hose to a point in the side yard below the level of the cellar floor and some 50' away from the house. No way am I going to add load to my septic system just to keep the cellar dry. You all saw those pics several years ago.

Captain Ned wrote:

That should do the job. I assume this is pumping into a city sewer line? If so, no worries about freezing or other nasties.

Unfortunately, no. I've only had it freeze up on me once though.

Captain Ned wrote:

Mine, OTOH, pumps out the cellar window and through a long flex hose to a point in the side yard below the level of the cellar floor and some 50' away from the house. No way am I going to add load to my septic system just to keep the cellar dry. You all saw those pics several years ago.

The pipes (one each for main and backup) exit through the wall of the house about a foot above ground level, then the water goes through approximately 25 feet of flex hose to a nearby storm drain.