1 GPM "SINGLE FIXTURE" WATER PUMPS FOR SMALL RVS
The posts above relate to "standard" RV water pumps in the 3 gpm range. These come with 1/2 inch hose fittings for both inlet and outlet, and generally require a 10 amp RV fuse.
Should you need to replace a 1 gpm "single water fixture" pump in a small RV, these have smaller 3/8 inch inlet/outlet fittings due to their lesser flow, and usually require a 5 amp RV fuse.
For some reason the 1 gpm pumps tend to operate at lower pressures (typically 30 to 35 psi) than the 3 gpm pumps (typically 45 to 55 psi), perhaps because it's anticipated that pumps for small RVs will have shorter lengths of plumbing to push water through, and therefore less overall flow resistance to overcome via a higher pressure. (Imagine pumping a gallon of water through 10 miles of pipe versus 10 feet of pipe. HUGE difference. Pumps push...but pipe and fittings push back.) So long as you keep pressure below 60 psi in a common PEX RV plumbing system (generally white, red or blue tubing rather than older gray tubing, the industry standard since circa 2000), you should be fine.
In addition to the off-brands of 1 gpm pumps, here's two name brands:
FLOJET
-#RLFP122202A or #LF122022
-12 volts
-1 gpm
-35 psi
-3.5 to 4.0 max amps
-5 amp or higher RV pump fuse
-Bypass valve to reduce cycling and pulsation
-56 mm x 84 mm mounting hole spacing
-Run-dry survivability
-Two 3/8" barbed fittings included, strainer sold separately. Can use Flojet #01720023S or #01740-003S in-line 3/8" strainer or generic via search of "3/8 pump strainer."
-2 year warranty
SHURFLO
-#105-003 OEM or #105-013 Aftermarket, same pump
-12 volts
-1 gpm
-30 psi
-2.5 to 3.0 max amps
-5 amp or higher RV pump fuse
-57 mm x 81 mm mounting hole spacing
-Run-dry survivability
-Two 3/8" barbed fittings included, strainer sold separately. Can use Flojet #01720023S or #01740-003S in-line 3/8" strainer or generic via search of "3/8 pump strainer."
-1 year warranty
It's easiest to replace a standard pump with a standard pump, and a single fixture pump with a single fixture pump. The original pump choice made by your RV builder is most likely accurate, with little need to upsize or downsize for most folks. But should you want or need to switch from one flow range to the other, you'll need to address both the differently sized fittings and possibly fuse amperage and switch amperage as well. You may be able to find different threaded adaptor fittings to do so. If not, simply use barbed hose adapters via an InterTube search of "reducer barb 1/2 3/8." #APXC1238 is carried in Home Depot stores, #BHB-393NL (sharper and better barbs -- you can use it as a prison shiv) is carried in Lowes stores, and also see #RF885 online. For a simple coupler to join two pieces of 3/8" tubing together, see #BHB-290NLB, #APXC3838, or Everbilt #800069. For potable 3/8" reinforced vinyl tubing (3/8" ID, 5/8" OD), see Eastman #98627, EZ-Flo #98626, Everbilt #HKP002-PVC001, or generic bulk hose on EBay. Use proper, small hose clamps that max out close to 5/8" such as Ideal #6260419, Apollo #IDL15 or Everbilt #6260294. Note that some of the generic 3/8" strainers have a bizarre 0.492" outer dia. barb that is intended to fit both 3/8" and 1/2" tubing, so read carefully and consider paying extra for the Flojet strainer. Flojet states that 3/8" barbed hose fittings (and therefore the entire water system) can flow up to 2.1 gpm, so a standard 3 gpm pump can't likely be fully utilized to its capabilities in a 3/8" system.
Or you can train your dog to push a manual hand-pump with his paws whenever you're in your RV. Trust me, he'll do it for hot dogs.
