If you've ever wakened your dry camping neighbors or a coach full of people with a midnight bathroom break, then you understand how noisy some water pumps can be when used. And by the same token, you may have taken a shower when another person started washing dishes, teaching you something about water pump flow limits. Fortunately, there's a relatively easy fix that can help to eliminate future issues with water pumps.

RV Magazine tested SHURflo's Extreme Series Smart Sensor 5.7 (which delivers 5.7 gallons of water per minute at 65 psi) and the smaller 4.0 water pumps and learned that they both offer the same multifixture, quieter operation found on big, pricey Class As and full-time fifth-wheels to the smaller Class Cs and toy haulers.

The Extreme Series Smart Sensors, as they are called, won't change your water capacity, but we learned they will provide a substantial increase in water pressure and flow efficiency. The good news is the installation took us only 60 minutes, and there's a good chance you can do it yourself with no special tools. Our installation required only a drill, screwdrivers, wire cutter/stripper/crimper and a test light.

Smart Sensor 5.7 and 4.0
The Smart Sensor has a five-chamber pump section and microprocessor that reads both pressure and amp draw, so it varies motor speed and water flow using pulse width modulation. If your RV was built within the last 10-15 years, the stock PEX plumbing should be satisfactory. But if it uses older polybutylene-tubing (plastic resin) water piping, you'd be better off with the Smart Sensor 4.0 (4 gpm at 50 psi), especially if you don't plan on replacing the tired water lines.

Although the threaded fittings are standard, the Smart Sensor 5.7 is a physically larger pump (9.25x5.0x4.72 inches). The 4.0 measures 8.25x5.25x4.75 inches. Both will fit in or near most factory water pump locations. However, if yours is crammed in somewhere, be sure you have the space to locate it. On our dummy coach, the compartment had plenty of space originally that had been compromised by two batteries and an inverter, so we mounted the pump upside down on the compartment ceiling (the pump's orientation is irrelevant).

You also need to verify you have adequate power supply; at peak draw, the Smart Sensor 5.7 uses a full 10 amps and is protected by a 15-amp inline fuse (SHURflo recommends 12-gauge wire). We upped the standard 10-amp water pump fuse in the DC panel to a 15-amp, and the 10-gauge wire at the pump pigtail was only a 6-inch run, so we kept the wires and the plug. A Smart Sensor 5.7 pump (or the 4.0 if you don't need as much flow) can be installed in any RV with 12-volt DC power. In the very unlikely event your plumbing uses nonstandardized fittings, some adapters will be needed, but even this isn't rocket science.

Since it varies output according to demand, the Smart Sensor doesn't cycle on and off like a conventional pump, cutting down on pressure spikes applied to the water system. It also means that unless maximum flow is required, the pump won't be running at full speed, which is another reason it's quieter; on identical mounting surfaces, the Smart Sensor is notably quieter than a conventional pump, but noise is relative to pump and line isolation (PEX piping is somewhat stiffer than earlier materials), so poorly installed water lines will still transmit some of the vibration. A "silencing kit" that consists of a pair of 30-inch flexible hoses will help isolate the pump further.

The Smart Sensor 5.7 retails for just over $200-roughly 50 percent more than a conventional 2088 pump-plus $19 for the matching Extreme Series 254 strainer (other strainers are available to match space and budget constraints) and $20 for the silencing kit (we found multiple websites listing both the 5.7 and 4.0 for under $150). The warranty period is three years, again 50 percent longer than that of a basic pump.

There really isn't much more to know about water pumps, except that a good aftermarket pump can save you a lot of headaches. Before you make up your mind about the product, ask yourself, how much is running water worth to you in the shower?