Reuben's Home Inspection Blog


What will happen when your sump pump fails?

Most houses with sump pumps rely on the pumps to keep the basement from flooding.  When a big rain storm comes through, the sump pump will really be needed... and that's also the time that the power to a  neighborhood is most likely going to get knocked out, disabling the sump pump and allowing the basement to flood.  This happened to a lot of homes in North Minneapolis this spring after the tornado came through.

If your sump pump quits working, will you know about it before your basement floods?  Do you have a backup in place?  Does it work?  Are you sure?  If you depend on a sump pump to keep your basement from flooding, it's important to have a backup system in place, just like it's important to back up the hard drive on your computer.

It's one of those things that most people don't think about until it's too late.  If you want to protect your basement from flooding, get a backup system.  There are a few different backup systems available.

Secondary Electric Pump

A secondary electric pump would be a good option to keep your basement from flooding in the event that your primary sump pump failed.  The secondary pump would need to be installed a little bit higher in the sump basket than the primary pump.  The downside to installing one of these is that if the power to your house went out, the pump would be useless.

Battery Backup

Backup Sump PumpBy far, the most common type of backup sump pump system that I've encountered is a battery powered system.  This consists of a big heavy battery that's about the size and shape of a car battery, as well as a backup sump pump that sits in the sump basket a little bit higher than the primary pump.  This system will save your basement from flooding if your sump pump fails or your power goes out. 

The Basement Watchdog is a brand that makes backup batteries with a warning to tell you if the battery has a problem.  This is a good feature to have, because I find that many backup batteries are dead.

If you already have a backup battery for your sump pump and it doesn't have a warning to tell you if the battery is dead, you should test it periodically.  You can simply unplug your standard sump pump and fill the sump basket with water using a garden hose to test the backup pump.

Hydraulic Pump

Another backup option for your sump basket is to install a pump that is powered by the municipal water pressure coming in to your home.  The nice thing about hydraulic pumps is that you don't have to worry about keeping a battery charged all the time, and if you have an extended power outage, you won't have to worry about the pump failing.  

The downside to using a hydraulic sump pump is that they're not nearly as powerful; the video below shows just how slow they pump water.  The original video was nearly three minutes long, so I cut out the middle as it got a little boring.


If the water at your home is supplied by a well, a hydraulic backup pump obviously wouldn't be any good, as a power outage would also knock out your well pump.

High Level Alarm

High Level Water AlarmNo matter what type of system you have installed, it's a good idea to have a high level alarm installed in your sump basket.  These alarms will sound off if the water level in your sump basket gets too high, and you can buy one for under ten bucks at Home Depot.  If you don't have a backup system in place, these alarms will at least tell you that you have a problem and you need to jump in to action.

I inspected a very nice home this year that had a completely finished basement that definitely could have benefited from one of these high level alarms.  This house had in-floor ductwork; when the sump pump failed, the ducts ended up filling up with several inches of water.  Click these links to see photos of the flooded ductwork and flooded ductwork 2

The water level in the sump basket never got high enough for the basement floor to get wet, but the standing water in the ducts acted like the worlds largest whole-house humidifier, which caused major condensation throughout the basement; even the outlet covers were dripping with water.  If the sump basket had been equipped with a cheap little high level alarm, this never would have happened.

If you want to have a backup sump pump professionally installed, hire a plumber to do it.  Mark Jerde with RM Mechanical tells me that he has installed dozens of these systems.


Reuben Saltzman, Structure Tech Home Inspections


Comment balloon 29 commentsReuben Saltzman • July 05 2011 06:49AM


Hi Rueben,

Very good info for a lot of "northern folks". Here in new Meico we don't really have many basements. And no rain for nearly ten months now. Even if we had a basement. No rain means no water in them.

Have a great day.

Clint McKie

Posted by Clint Mckie, Desert Sun Home, Comm. Inspection 1-575-706-5586 (Desert Sun Home, commercial Inspections) over 7 years ago

Excellent post, very useful information and a timely warning to most of us.

Calling a local plumber today ( Toronto /Canada ) to work on a strategy... does home depot carry the battery backup?



Posted by Nor Yeretsian, Envoy Capitol Realty Inc., Brokerage Toronto (Envoy Capitol Realty Inc.) over 7 years ago

Clint - that sounds nice for you guys, in a way.

Nor - yes, Home Depot sells them; click on the photo above to go to their site.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

Rueben, this is excellent advice. I am making a note of it for my clients. Thanks...

Posted by David Burrows, No Pressure, Just Seriously Devoted to Real Estate (Classic Realty) over 7 years ago

Absolutely.  My advice to every single home I sell with a sump pump is "get a battery back up for when the electricity goes out.

That was the first thing I did when I bought my home 5.5 years ago. 

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley,, MD & VA Homes and Real Estate) over 7 years ago

Hi Reuben - This is great information.  We have quite a few properties with sump pumps and people always have questions about them.

Posted by Peggy Chirico, REALTOR® 860-748-8900, Hartford & Tolland County Real Estate (Prudential CT Realty) over 7 years ago

I discuss this with buyers all the time.  When they ask why there is a battery beside the sump pump, my answer is, "Life experience!"  And the time to buy one is when there is a big pyramid of them in the store, NOT two days before the hurricane hits!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) over 7 years ago

Hi Reuben. Thats a great post and good advice for homeowners. The Scout's motto " Be Prepared' is worth following in this case.

Here we often see the hydraulic pumps being installed.  They are good but the municipalities discourage their use as their concern is maintaining the water supply and pressure (for fire), so the use of these pumps may not be allowed in a given municipality.

Posted by Robert Butler, Montreal Home Inspector | Aspect Inspection (Aspect Inspection) over 7 years ago

Reuben....excellent reminder to homeowners with sump pumps.  Many people don't realize they are not working or that they need a backup plan until it is too late.

Posted by Christine Smith, Exclusive Buyer Agent & Attorney, Canton, MA (Buyers Brokers Only LLC - over 7 years ago

David - thanks.

Lenn - I waited several months before installing mine.  Terrible, right?

Peggy - and it's so important to have 'em working!

Jay- exactly.  You especially don't want to be trying to install one of these systems after your power goes out.

Robert - interesting point about municipalities not wanting them because of the increased demand in water.  I haven't heard anything like that in my area yet, but these hydraulic pumps seem to be a new thing that's just starting to catch on.

Christine - you got it.  I always test the backup batteries while inspecting houses, and I've found the batteries only still work about half the time.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

Reuben, I have a battery back-up sump, but I think the high water alarm also has merit.  I am re-blogging this as we have many homes in

Posted by Chris Smith, South Simcoe, Caledon, King, Orangeville Real Esta (Re/Max Chay Realty Inc., Brokerage) over 7 years ago

You may have dodged a bullet.

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley,, MD & VA Homes and Real Estate) over 7 years ago

Super post, Reuben. I have seen this happen way too many times.  Yes, you need a back up system. I can't even tell you how many times we've replaced carpet, hardwood and laminate in the basement because of this and the damage often goes well beyond the floor into the walls.  So avoidable.

Posted by Debbie Gartner, The Flooring Girl & Blog Stylist -Dynamo Marketers (The Flooring Girl) over 7 years ago


Here we see them more in crawl spaces than in basements. And, down there, they are often not functional and nobody even knows about it.

Posted by Steven L. Smith, Bellingham WA Home Inspector (King of the House Home Inspection, Inc.) over 7 years ago


We have basements in my city but I have never had a property inspector recommend a back up battery.  I will ask them about it next time I seen them.  We may not need them here.

Posted by Evelyn Kennedy, Alameda, Real Estate, Alameda, CA (Alain Pinel Realtors) over 7 years ago

I've seen a lot of dead sump pumps. I often wonder if sellers ever check them?

Posted by Lizette Fitzpatrick, Lizette Realty, Lexington KY MLS - Kentucky Homes (Lizette Realty - Richmond KY) over 7 years ago

Since we didn't have a basement at the time, our septic tank waste came up through the main floor bathroom drains/toilet when the sump pump failed. We ended up having to put in a new septic tank next to the house because it had been on a hill above the house and no pump seemed to be able to handle the uphill journey.


Posted by Mel Ahrens, MBA, Kelly Right Real Estate, Customized Choices for your Real Estate Needs (Kelly Right Real Estate) over 7 years ago

Unfortunately we learned the hard way when we lost power and our sump pump!!!  This is an excellent example of what happens when you live in a flood prone area and lose power.  Now only if I had read this 8 years ago lol!  I'm going to reblog for my Fairfield friends!

Posted by Gina Chirico, Real Estate Agent - Essex County, New Jersey (Lattimer Realty) over 7 years ago

Most people probably don't learn the lesson you explain until it's too late and they have a huge and costly mess on their hands.  The advice to buy the alarm is so simple and cost effective that can save you so much time and money.

Posted by Eileen Hsu, LICENSED REAL ESTATE SALESPERSON (Douglas Elliman Real Estate) over 7 years ago

I will share this advice - I am guessing most people won't listen, but it's good to know!



Posted by Joy Daniels (Joy Daniels Real Estate Group, Ltd.) over 7 years ago

Reuben, what I find equally frustrating is all the "unnecessary" sump pumps where gravity was an option :)

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) over 7 years ago

Chris - Yeah, I need to order one of these backup alarms for myself as well.  Thanks for the many re-blogs!

Lenn - I think you're right :)

Debbie - exactly.  I'm sure the lack of these things helps keep you busier!

Steven - I can understand how it would be so much easier to forget about these in a crawl space.

Evelyn - If there's a need for a sump pump, a backup battery would definitely be a good thing.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

Lizette - nope :).  Just like most people probably don't check the data on their backup hard drive to make sure it's all there (guilty)

Mel & Gretchen - I bet that wasn't cheap.

Gina - I bet you check on your battery too now?

Eileen - exactly.  Ten bucks!

Joy - thanks.

Charles - Are you talking about houses with bad grading, no gutters, and a full drain tile system, or houses with sump baskets that could be discharging to daylight instead?  I find plenty of the former.  

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

I'm a plumber in the Toronto area. Our company will NOT install these type of battery backup sump pumps. Over the years we have seen so many flooded basements due to various unreluablity issues with these units.

There is no way to test the charge capacity of the battery which descreases with age. The pump may run for only a couple of minutes. Also the pumping capacity is so low that they often can not keep up when the power goes out. We have seen bad check failures that causes the water to only to be recirculated in the sump. Also stuck floats and water vapour locks .. I could go on and on.

We only install Nexpump systems now. Twice the pumping capacity of your main pump whenoperating off batteries. It tells you when the battery needs replacement and shows how much time is left on the batteries when power is off. It has no floats to break or get hung up. It tells you when a problem has happened and takes alternate action to avoid flooding.

It's expensive but it works better than anythingelse on the market.

Posted by A Plumber over 7 years ago

Hey Plumber, thanks for the input.  I've never seen the Nexpump systems before.

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago

Excellent post.

Every homeowner with a basement or a crawl space should have a working sump pump and backup. Not just those living in a flood prone area.

When it comes to flooding there is no such a thing as a flood safe area. According to the US 20% of all yearly flood insurance claims com from low-to-moderate flood risk areas.

A word of advice:

Consider that a backup sump pump is usually not needed most of the time. It is a "worst case scenario" device. It is only needed when the main pump fails, the power goes out, or in exceptionally heavy rains. Under normal conditions, and with a properly maintained system, it may be years before you need that backup pump to kick in.

The problem with many of these hardware store brand battery opperated backup pumps, is that they are tied to adapted marine batteries, which are not made to be innactive for long periods of time. If not used often they lose power and even die. That means that the battery may be very weak or even out of commission when you need it most.

The UltraSump backup pumps, the only type we install, both as a stand alone product or as part of our SuperSump and TripleSafe systems, have a battery that is specifically developed for this purpose and, as long as it is kept charged, it will not lose power if it stays innactive for a long time.

Posted by Cynthia Freeney (Basement Systems Inc) over 7 years ago

Great post explains a condition that I do not see that much. Arizona homes have few basements so this is a total unknown for me

Posted by Jack O'Neal (Conway Real Estate) over 7 years ago

Interesting - we don't even have basements down here in the sunshine State!

Posted by Barbara-Jo Roberts Berberi, MA, PSA, TRC - Greater Clearwater Florida Residential Real Estate Professional, Palm Harbor, Dunedin, Clearwater, Safety Harbor (Charles Rutenberg Realty) over 7 years ago

Cynthia - how does your system compare to the Nexpump system?  I've had a few people brag about those...

Jack - thanks.

Barbara-Jo - you don't need 'em :)

Posted by Reuben Saltzman, Delivering the Unbiased Truth. (Structure Tech Home Inspections) over 7 years ago