Low-Profile Battery Backup Sump Pump


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"Easy to Understand, Easy to Install, Easy to Maintain"

DH900-M Maintainer pump with compact float mounted on its side.

Hydropump Model DH900-M

The Easy-To-Install, Do-It-Yourself battery backup sump pump "maintainer," that fits in almost any sump, anywhere, REALLY!

This battery backup for existing sump pump includes everything you need for a typical installation, except the battery (and we sell those separately, too!). This pump can typically be installed in less than an hour, using a unique stainless steel bracket to mount the pump in the sump. The float mechanism is mounted on the pump itself and has no moving parts. There is no adjusting or guesswork involved. As a "maintainer" pump, the pumping "range" is simply designed to keep the water from rising up to reach the floor.

  • A battery seems to "regenerate" or recover somewhat on its own during off cycles.
  • During the more frequent "off" cycles achieved using shorter run cycles, the battery "recovers" or "regenerates."
  • Instead of trying to pump down the sump in the same manner as the primary electric pump, this pump does what it was originally intended to do: keep the water off the floor during a primary sump pump failure.

The DH900-M uses a very low-profile switch

It has no moving parts and doesn't protrude further than the base of the pump. It pumps approximately 2" of water during each cycle so that the DH900-M:

  • Maintains a safe water level instead of trying to remove as much water as the primary pump, which can certainly remove more...if the power was on.
  • Gets about the same number of hours of pumping as many of its competitors.
  • Keeps the water off the floor for many hours, maybe several days if the cycles are spread out enough.
  • Stays out of the way when trying to fit a backup sump pump in a crowded sump, even when there are 2 or 3 other pumps and floats and wires and alarms, etc.

How long will the DH900-M Maintainer Pump operate?

If your sump pump usually
operates every:

Your sump then receives “x”

Gallons per hour (GPH):

The Maintainer will run for:


600 GPH



300 GPH



150 GPH



100 GPH



75 GPH



60 GPH



comes complete with its own stainless steel mounting bracket to easily set the pump at the desired level in the sump. The pump typically stays at or slightly above the normal high water line. Its job is to keep the floor dry until the problem with the primary sump pump is resolved. If your sump is standard size (18" across and about 22-26" deep, or as small as 10" across and 10" deep, this model will most likely fit with your existing primary sump pump. Its most important feature is the switch that has no moving parts.

  • No float to get stuck.
  • Nothing to interfere with your other float, or floats.
  • DH900-M comes without a battery, as shown below.

We can ship the total package right to your door in one easy transaction! By the time you would have figured out which battery to get and then go buy it, ours will probably be at your door, ready for installation!

Hydropump Model DH900-M

Hydropump DH900-M showing all the included parts. (No battery)

Hydropump Model DH900-M
Battery not included

Price: $269.00

Installation Instructions

Hydropump DH900-M drawing of typical installation in sump with primary pump.
  1. Attach pump bracket to floor bracket and hose to pump.
  2. Lower pump into sump in final position.
  3. Unplug primary sump pump, drain discharge pipe, connect tee assembly and discharge hose to primary pump discharge pipe
  4. Insert battery into case and connect cables from charger and pump.
  5. Plug in charger.

Fill sump with water to test pump. When water reaches top circle on float switch, pump will turn on. As it pumps the water down past the lower circle, the pump will stop. This works magnetically and is totally safe and reliable.

Tip: You may also test the pump by placing one finger on each circle at the same time. The switch senses the resistance in your fingers as if it were water and starts the pump. Remove your fingers and the pump stops.

Included Items:

  • High quality pump motor with heavy duty plastic case. Can't rust, rot, or corrode.
  • Stainless Steel pump mounting brackets. Strong, durable, adjustable.
  • Built-in, low-profile float switch with no moving parts. Does not extend beyond the footprint of the pump at any time.
  • PVC tee, check valve, and hose fittings. Should be all the fittings you need.
  • One Heavy-duty plastic battery case and cables. (A second case is available (Part# DBC) to add a second battery to double pumping time.)
  • 1 Amp float/maintainer charger with status lights and both ring and alligator clip terminals. Compatible with any Marine deep cycle battery. Capable of maintaining a maximum of two batteries.
  • Flexible discharge hose and clamps. Makes installation simple and easy.
  • High water alarm included, that warns you when the water is above normal and pump is operating.
  • Complete, easy to follow, illustrated installation instructions.
  • TWO YEAR Limited Warranty

Will it fit in my Sump?

Here's a great comparison photo. Look at all the room you got in there! That's a standard size sump that is 18" across at the top and 26" deep.

DH900 vs 1 Pound Coffee Can: Size ComparisonHydropump DH900-M in standard sump with primary pump

Product Specifications and Service Requirements


  • One12 Volt Deep Cycle Marine, Sealed Lead Acid, AGM, or Gel Type Battery (optional second battery may be used). We recommend the use of a maintenance-free battery.
  • Battery sizes 27 - 31 typically fit the case: (Battery not included)
  • In order to fit our case, the battery size cannot exceed 13-1/2" L x 7" W x 10" H to top of terminals.
  • Charger Included: 120VAC, 60HZ Power Outlet, 1 amp./hr.
Hydropump Model DH900-M
Pump Base Dimensions 6-1/2"
Pump Height 7"
Pump Weight with Base 7 Lbs.
Shipping Weight 15 Lbs.
Discharge Hose Size 1" 
Main discharge pipe size 1-1/2"
Pumping Rate Gallons per Hour
At 5 Feet 1300
At 9 Feet 900
Max. Head in Feet:  11
If pump cycles every: 1-minute 5-minutes 15-minutes
On 1 battery (Double for 2 Batteries) 12hrs 48hrs 96hrs


  • DH900-M (Battery not included): Only $189.00!!

Buy Now

Click here to see Batteries for Backup Sump Pumps

Customer Satisfaction Guarantee

Within 30 days of purchase, if you are not completely satisfied with your new Hydropump, Base Products Corp. (The Company) will refund your money, in full, excluding shipping charges. Pump must be in its original package with all parts included and in salable condition. Please contact the dealer where you purchased your pump to obtain refund. If purchased directly from The Company, you must call our Customer Satisfaction Department at 1 800 554 1426 to process return or to receive Technical Assistance. Please give your name, address, phone number, date of purchase, and address of the installation.

Two Year Limited Warranty