Login
Start Free Trial Are you a business? Click Here

Saniflo 21 Residential Water Pump, Grey,1/3 HP Reviews

4.6 Rating 125 Reviews
Read Plumbing Supply and More Reviews

The Saniflo MPN 21 residential water pump transforms basement remodeling projects by eliminating traditional drainage limitations through its specialized 1/3 HP motor configuration. This grey-colored thermoplastic housing unit measures exactly 8.75 inches in height, 9 inches in width, and 10.25 inches in depth, positioning itself as the compact solution for residential drainage challenges where gravity flow proves impossible.  Weighing 13 pounds, this Saniflo pump delivers 18 gallons per minute discharge capacity at its maximum 14-foot vertical lift specification, making it the definitive choice for basement apartments, laundry installations, and remote kitchen additions where conventional drain systems cannot reach the main sewer line. Unlike standard sump pump configurations designed for groundwater removal, the MPN 21 features three strategically positioned 1.5-inch inlets—two low-profile side inlets with integrated check valve protection and one top-mounted inlet—enabling simultaneous wastewater collection from multiple fixtures without requiring complex manifold assemblies.  The unit's 120-volt, 60-hertz electrical specification draws a maximum 4.5 amperes during operation, qualifying it for standard residential circuit integration while maintaining CSA certification under both IPC and NSPC plumbing code standards. Precision-Engineered Oil-Filled Motor Technology Delivering Maintenance-Free Performance The permanently sealed oil-bath motor assembly within the Saniflo 021 eliminates traditional maintenance intervals found in conventional drain pump applications. This 0.3 horsepower induction motor operates at precisely 3,600 revolutions per minute, driving a direct-coupled impeller through a single spindle shaft that minimizes mechanical complexity and potential failure points.  The oil-filled enclosure surrounding the motor provides continuous lubrication, thermal protection through efficient heat dissipation, and acoustic dampening that reduces operational noise to just 44 decibels measured at three feet—quieter than most residential dishwasher cycles and significantly below the threshold requiring hearing protection in occupied spaces. The thermoplastic housing material surrounding the motor assembly resists corrosion from prolonged wastewater exposure while maintaining structural integrity at operating temperatures up to 140 degrees Fahrenheit.  This temperature threshold accommodates hot water discharge from washing machines, dishwashers, and utility sinks without requiring cooling periods or thermal protection devices. The polyethylene construction also provides chemical resistance against common household cleaning agents, laundry detergents, and kitchen effluent containing mild acids or alkaline compounds. Engineering specifications reveal the motor's 30-microfarad capacitor rating ensures consistent starting torque under varied load conditions, preventing the motor stall issues that plague less sophisticated residential pump designs.  The pressure switch activation mechanism responds to water level changes within the 2.75-gallon capacity chamber, triggering motor engagement only when sufficient volume accumulates for efficient discharge cycles lasting between two and ten seconds depending on horizontal pipe run configurations and vertical lift requirements. Three-Inlet Configuration Maximizing Installation Versatility Across Residential Applications The Saniflo MPN 21's triple inlet design accommodates diverse fixture combinations without requiring additional collection pits or intermediate pumping stations. Both side-mounted 1.5-inch inlets incorporate factory-installed check valves that prevent backflow during system operation, eliminating the need for separate valve installation and reducing potential leak points in the drainage assembly.  These low-profile inlets position just above the unit's base, facilitating gravity drainage from floor-level shower bases constructed on minimum 6-inch elevated platforms using dimensional lumber framing techniques. The quarter-inch per foot slope requirement toward the pump ensures consistent flow without standing water accumulation in horizontal drainage runs. The top-mounted inlet provides alternative connection routing for fixtures positioned above the pump housing,

Visit Product Page
“Using this for a pedicure chair. It discharges quickly, but it doesn't run in one smooth motion, it surges to discharge the water. I'm not sure I would have spent so much for this pump had I known it functioned this way. I've owned other cheaper discharge pumps and they worked just as well.”
Helpful Report
Posted 10 years ago
“Good products, will buy again if needed!”
Helpful Report
Posted 11 years ago
“I can't speak to longevity yet, but I can tell you that this saved me a plumbing nightmare of getting into a tight dirty crawlspace with old plumbing. The plumbing stack was in a bad place and above the tub drain, so I ordered this, easy install, and problem solved.”
Helpful Report
Posted 11 years ago
“Functions exactly as described. Very compact unit, installed for a wet bar. Instruction sheet awful at best. Plumber had difficulty finding the vent outlet (a well hidden knockout), but followed a prior Q&A response and called Mark. ("The max vertical is 12 ft on the Sanishower, so this unit will not work for that situation. The Sanivite is a gray water pump that can elevate to 16 feet, check out that one. If you have any questions feel free to call us 866-658-0505 Thanks, Mark The SanifloStore). Mark was available and very helpful. Highly recommend.”
Helpful Report
Posted 11 years ago
“This pump solved my basement shower plumbing nightmare. I was able to avoid a costly demolition and got my project done.”
Helpful Report
Posted 11 years ago
“Excellent replacement for our old out dated pump! Easy to install! Pumps Great!”
Helpful Report
Posted 11 years ago
“good deal”
Helpful Report
Posted 11 years ago
“Amazing. My air conditioning unit required a hose to run across the middle of my basement floor to the drain. My basement is now finished, and I was able to run a hose around the perimeter of the basement, behind the walls, from the air conditioner to the drain. The pump pushes the water through the hose, uphill and around corners. No more ugly hose down the middle of my living space. It was VERY easy to install, just need an outlet nearby.”
Helpful Report
Posted 11 years ago