Vacuflush Lake Water Draw Advice

[Midnightsun]

There are only a few things that make us go back to port and one of them is running out of fresh water. Not so much so because we have no water since our water is almost drinking water but because the heads will not flush without water in the potable water tank. That being said, the heads take their water from the potable water tank pressurized supply and I would like to draw from the lake instead. I do have my washdown pump which already gives me this feature so basically rerouting the head water intake line to the washdown line sounds like a simple solution right? Anyone see any issues by doing this except that the washdown breaker needs to be on when using the head?

[Midnightsun]

Hmmm, got me thinking here. Probably better if I simply T off anywhere into the main pressurized water supply from the washdown circuit and install a solenoid to supply as required. Shutting off the potable water pump breaker, turn on the washdown breaker and activating the solenoid valve now supplies lake water throughout the entire boat without using any tank water or affecting the cleanliness of the potable water tank due to the check valve in the pump. Yep, think I will go this route as it gives much more flexibility to water supply overall. Activating the lake water supply when we do dishes comes to mind as lots of water wasted there not to mention showers in the morning!! Probably install a whole house carbon/sediment filter on this line as well even though I have one at the kitchen faucet already. Anyone see any issues here?

[Viper]

Personally I would keep both systems separate. The easiest solution if you want to use raw water is your first one to tee into the raw water wash-down. The downside is that raw water produces more holding tank odours and the same can be said about the standing raw water that will always be in your bowls, for those reasons, a fresh water flush is considered an upgrade. I know you can add filters but that's yet another item to maintain, and if the waters you're in have a degree of salt, I'd contact Dometic to ensure that won't affect system components. It may be fine, I've just never had to look into that before. If there's room for one, have you considered adding another water tank?

[Midnightsun]

Another water tank will run out eventually. I doubt I could ever drain the Great Lakes though.

[bud37]

Don't forget a couple of check valves in the appropriate spots to prevent unwanted back feed and siphoning.....watch your levels, don't want to sink the boat....maybe check to see if this raw water feed to sinks and main tank is an option on any boats...not saying it won't work, really don't know at this point, it seems fairly straight forward and would be handy to have this capability.

[Midnightsun]

Took a look at the installation difficulty today. Wash down pump is right beside my water pump and potable water tank so this will be easy. Another project that is going to happen.

[Midnightsun]

Decided to interconnect the entire system to supply lake water on demand. Will be installing a 5a breaker in the conveniently unused location under the washdown pump breaker and relabel to "interconnect". Need to shut off the potable water pump and turn on the washdown pump when activating so the location for this is really ideal. May install a small led reminder light in the galley in case we forget to deactivate the interconnect which is easily connected to the wire powering the solenoid.

Keep in mind the waters I boat in are really pristine and I would say drinkable in a bind. Would not recommend this modification in bad waters or salt water just like I would not activate it if I wander into bad areas and would refrain from using it in Marinas or other doubtful areas. This will mostly be used to save potable water when taking showers at times when we are away for several days. The main goal here is to not need to return to port because we are low on water and cannot flush the head. Bottom line this will be used infrequently but in place if needed.

[tomschauer]

I wouldn't even use our bay water to flush my toilet, let alone shower in. It is far from pristine.
Maybe some day.....

[Midnightsun]

Started a new thread on the modification, see here. viewtopic.php?f=13&t=3204&p=20764#p20764