Converting Heads to Flush with Freshwater


Last Updated on September 9, 2019 by Amy

One of the projects we tackled when outfitting our boat for cruising was converting our heads from saltwater to freshwater.

This was a project that I tackled on my own and I’m proud to say I completed the project with only about 4 trips to West Marine and no sewage leaks in the boat!  

Why You Should Use Freshwater instead of Saltwater to Flush Your Heads

  • When saltwater is pumped through the hoses in your head, small animals come up with it. The animals get trapped and die, resulting in a decomposition smell.
  • Saltwater and urine interact and form calcium deposits in the hoses. This can smell and also restrict the flow of water.

To combat this, you can regularly do vinegar flushes (helps with the deposits, but not really with the smell unless you clean out the intake hoses) or you can convert the heads to flush using freshwater, which eliminates the calcium deposits and the sulfur smell.

Supplies Needed

  • Jabsco Head Solenoid / Anti-Syphon Valve
  • Weld Mount Studs
  • Two-part Epoxy
  • 12-volt two-strand wire
  • Female connectors for the wire to the solenoid
  • New hose to go from the solenoid to the head (our old system had 5/8″, we switched to 3/4″, and needed adapters to do it)
  • New hose to go from solenoid to freshwater system (for us, 1/2″ hose)
  • Cap for old saltwater hose
  • Whale T-adapter for pressurized water system (so for us, 1/2″)
  • 1/2″ quick connect
  • Hose adapters if needed
  • Hose clamps as needed
Jabsco Solenoid
Jabsco Solenoid

Steps to Convert Head to Freshwater

  • Use the weld mounts and two-part epoxy to mount the solenoid near the holding tank and freshwater supply.
  • Run the 12 V wire from the pump up to the solenoid.
  • Splice the new 12 V wire to the pump wires.
  • Use female connectors on the other end to attach the wire to the solenoid.
  • Remove the saltwater hose from the pump. We added a cap and left the hose in the bilge so we can always easily replumb back to saltwater.
  • Run your new hose and attach one end to the head and the other end to the middle barb on the solenoid.
  • Turn off the freshwater pump.
  • Run a new freshwater hose from the right barb of the solenoid to where you will plug into the freshwater system.
  • Use the whale T-adapter to tie into the freshwater system.
  • Repower freshwater pump and check for leaks.
  • Test your head.

Watch the Video: Converting Heads to Freshwater

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