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Basement Watchdog

Model # BWD12-120C

Internet # 100065446

Store SKU # 130781

Big Dog Computer-Controlled AC/DC Battery Backup Sump Pump System

This item has been discontinued.
The Home Depot no longer carries this specific product.

$497.00 /each


Model # BWD12-120C

Internet # 100065446

Store SKU # 130781

Store SO SKU # 1000895759

The powerful Basement Watchdog Big Dog Computer-Controlled AC/DC Battery Backup Sump Pump System pumps 3,500 GPH at 0 ft. of lift or 2,200 GPH at 10 ft. of lift. This convenient pump fits next to the main AC pump and automatically begins pumping during power outages when the main pump fails or when water flow exceeds the capacity of the main pump. This reliable sump pump system features a 20 Amp charger that recharges the battery quickly and runs the pump with AC current instead of the battery if the power is on.

  • Pumps 2,200 gph at 10 ft. Lift and 3,500 gph at 0 ft. Lift
  • User-friendly control panel lights up with a warning and describes what to do for easy maintenance
  • A sensor monitors battery fluid levels for increased piece of mind
  • Runs pump once per week to ensure operation and backup pump will run directly on a/c power if available
  • Corrosion-resistant thermoplastic housing
  • Includes a dual float switch for added protection
  • Includes powerful 20 amp charger that recharges the battery quickly and shuts off completely to prolong battery life
  • Backup pump will run directly on ac power if available
  • Increase the run time by connecting two 7.5 Hour Batteries (30HDC140S) using the Basement Watchdog Parallel Jumper Cable (PJC – Available online). Additional acid pack (Z-Pack) required
  • Home Depot Protection Plan:

    Home Depot Protection Plan

Info & Guides

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Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
Amperage (amps) 
Batteries Included 
Battery Life (hours) 
7.5 h 
Battery Type Required 
30HDC140S - 7.5 Hour Basement Watchdog Deep Cycle Battery 
Housing Material 
Number of Batteries Required 
Product Weight (lb.) 
5 lb 
Voltage (volts) 
Warranty / Certifications
Certifications and Listings 
SSPMA Certified 
Manufacturer Warranty 
2 Years 


Rated 4.0 out of 5 by 30 reviewers.
Rated 1.0 out of 5.0 by Not all that's it's cracked up to be... I've owned this thing for a few years, and thought all was well. I've checked it from time to time, and it always says everything is fine. While the pump works fine, and I do catch the pump being tested from time to time, I found the maintenance of the battery is horrible. Evidently, it must overcharge the battery, as all through the water level indicator showed good, I decided to check anyway, and found the battery 1/2 gallon low. Ergh! I call and the tech says the water level indicators are notoriously unreliable so you have to check the batteries every 3 months. Well, how about fixing the sensor so it actually works right? Or, remove the feature so people don't rely on it. So I fill up the battery, charge them over night with my automotive charger, and let it rest a bit and find it's only holding around 12.2v. Great, a ruined battery. So, before I go to buy a new one, I hook up back up just to have something in the interim, and find that the system is indicating 12.2v is 100% !!! What? 12.2v fully charged is less than 25% capacity bordering on junk! Wow, it's pretty clear the charging and maintenance portion of this unit is garbage. I'd suggest that you do NOT rely on the battery level sensor and check it manually - and frequently. Then I'm going to find a way to disable the charging function and just use a battery tender so I'm sure they are being properly charged. You know, the thing that really gets me is, you spend top dollar because you want the piece of mind that your finished basement is protected. It's really irritating when you find out that your investment is just a mirage, as although it's showing all's well, the reality is, if I had had a long outage, this thing probably would have only lasted a few minutes due to improperly maintaining and ruining the battery. IMHO, you are much better off just getting a manual switched system, and use a battery tender as all of the fancy features of this expensive unit don't work correctly once you peel back the flimsy veneer. Better yet, use the ~$600 you'd spend on this system with the required battery and tax, and use that as a down payment on a NG backup generator that will offer real protection. When you factor in burning through $150 batteries every couple of years, its a no brainer. I've attached a photo of the control panel showing all's well, and the battery charge level is 100%, while the next photo shows the connected battery only has 12.20 Volts. Junk, Imho. December 29, 2014
Rated 5.0 out of 5.0 by Saved my basement many times This was the second system I have purchased and it has earned it's keep several times over. I live on 2 1/2 acres that are surrounded by wetlands. I have drain tile around the inside of my foudation so my sump pumps fill and drain about every 3 mins 24/7. So when the power goes out, which it has I can flood my basement 4" deep in 45mins. best thing I ever bought for the house besides the drain tile. Alarm goes off to tell me when the power goes off or there's a problem with the main pump. Only 1 problem. DON'T wait for the low water sensor to tell you when to fill with water. Do it once a year, trust me. I waited and we had a tornado that knocked out power for 4 days. Smoked the battery. Other than that, you can't go wrong. I own 2 systems. Well worth it. June 29, 2011
Rated 5.0 out of 5.0 by A Great Buy but..... EVERYONE READING THIS.... make sure you UNDERSTAND THAT THIS DOES NOT COME WITH A BATTERY OR ACID. I wish Glentronics would simply package the battery with this. Its sort of dumb.... you need a battery since the system will not work w/o it. Yet they sell it seperate. I ended up using a marine battery from my boat until I got time again to go to home depot to pickup the Glentronics / Watchdog battery. (Another $100). This is a great system. I have put it in unfortunately after the fact. Will the lesser models work.... yeah I imagine they would but when I saw the water pouring in over the sump pump cover after the power went out, it was scary to see how much water was coming in. Within 2 - 5 minutes, our basement (approx 2000+/- sq ft) was covered in about 2" of water. Soooo that being the case, I opted for the most GPH pump. I was thinking about putting in a generator but decided on this for the interim. This unit also gives you more information feedback than the other 2 lesser models. It also tells you how much more battery life is left. October 3, 2006
Rated 5.0 out of 5.0 by A must have for basements with sump pits This product has saved my basements on several occasions. The system has a powerful pump, charger, several monitoring features and easy to follow step by step instructions on how to install and troubleshoot the system. The company also has outstanding customer service. I used two 7.5 hour Watchdog batteries (in parallel) for each system which provides days pumping capacity. You would need a parallel jumper cable which I bought from the manufacturer. One piece of advice…although the system monitors the battery fluid levels, which works very well, I like to check mine when I turn the clocks back or just before going on vacation. Overall great product!!! December 30, 2009
Rated 5.0 out of 5.0 by BONUS--it's compatible with an AGM battery DItto other Excellent reviews. The only thing I'm adding is the fact that the electronics on the Big Dog model (as well as the inexpensive BWE ) are fully compatible with an Absorbed Glass Mat (AGM) battery according to Tech Support. Why is that important? Because, AGM batteries don't produce hydrogen gas when they charge--so pilot lights and other ignition sources in the basement pose no problems! They won't leak or spill even if they're broken, they survive most freezes, and warranties are twice as long as a lead -acid design. (I am NOT an advertiser--just a very happy camper) April 14, 2010
Rated 5.0 out of 5.0 by I bought the Watch Dog battery back up system last summer after installing drain tile in my constantly wet basement. My sump pump now runs 24/7/365. We had so many power outages last summer that I flooded the basement several times. I purchased the Watch Dog system and have been dry for the first time since moving here 9 years ago. It has saved me from bailing water from the pump well to renting a generator numerous times. Last week the main pump failed and it was 3 days before someone could come and replace it. The Watch Dog took over, running on A/C electrical from the house and when the company came to replace the main pump he told me with the amount of water we have it's a good thing I bought that system. Awesome Product!! April 11, 2009
Rated 4.0 out of 5.0 by It Works and Has Good Displays I installed the pump myself (no experience). You just need to be willing to cut and glue PVC. It took 2 hours to install. The operation of the pump is very straight forward and easy to understand. The controlling unit has good displays. One month after installing, a big storm knocked out our power. The unit kicked in and took over for the 4 hours we were without power. Water was coming into the sump fast, but it had no problems keeping up. You may be happy with the cheaper versions, I don't really know all of the differences. I do know that I have peace of mind with this thing installed. I would have rated it as 'excellent' but at $560 including battery and acid, it seems like a good value (not an excellent value). June 11, 2008
Rated 5.0 out of 5.0 by $600 or $6000 you decide. This is the best backup system you can buy. I paid about $600 for complete system and installation, and is the best money I ever spent. It has saved my basement time and time again from the unrelaible power company, and bad main pumps. My system is almost 5 years old, same battery with no issues; it even tells you when you need to add distilled water. This unit is completly relaible. When storms roll in and power goes out, my wife and I sit back and just watch the storm pass by without a worry. If you are unsure about buying a unit and you have a finished basement think about this. A estimate for restoration company to come out and reapir damge to your capreting, walls etc can cost $6,000 to $10,000! How do I know? Because several of my friends and familiy didn't take my advice on the WatchDog and paid thousands out of pocket. Additioanly most insurance companies cover very little, natl avg only $5,000 (unless you ask for more coverage and pay a higher premium) after you pay your deductible. My $600 INVESTMENT PROTECTION (WatchDog) has easily paid me back 10 times over. Go get it now before the next storm washes away your rainy day savings. August 12, 2007
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