Leaving the boat for a week - Water tank empty or full?

[flightlead404]

Newbie 1 week into boat ownership.

I'm leaving the boat for a week in Ft. Pierce.

water tank">Fresh water tank just emptied. I have the option of leaving it empty until I return and filling it then, or filling now and letting it stand.

I use a 2-stage 20 and 5 micron filter household (10") water filter to filter incoming water.

Does it make a difference? I'm inclined to leave it empty.

[Tomodore]

one week doesn’t matter

[Gudgeon]

One week is no big deal. Is it on a mooring on in a slip. In our marina everyone looks out for each other. Maybe let you neighbor know you are gone for the week and give them your phone number. I will leave water in my tanks for three months then dump it if not used.

[Marathon1150]

I share the view that it doesn't matter - empty, partially full or full.

We often left water in the tanks for months at a time but dumped it when we returned to the boat. We also used a UV unit, carbon block and 5 micron filter on all of the water going into those tanks.

I do however turn off the water pressure pump.

[flightlead404]

Pumps will be off, shore side water supply disconnected.

Glad to hear its not a big deal either way.

[GreenWave]

Yep. Not a problem if the pump is off and never leave the shore water connected when not there.

[Joh.Ghurt]

In general the advice is water tanks empty, fuel tanks full.

Add biocide to the fuel before you leave, rinse the water-tanks when you return.

However for 2 weeks or a month, it doesn't matter at all. Just make sure you don't leave the filling-caps open.

[patrickbarbary]

It does not really matter but I prefer keeping them full.

[MJH]

Originally Posted by flightlead404

Newbie 1 week into boat ownership.

I'm leaving the boat for a week in Ft. Pierce.

Fresh water tank just emptied. I have the option of leaving it empty until I return and filling it then, or filling now and letting it stand.

I use a 2-stage 20 and 5 micron filter household (10") water filter to filter incoming water.

Does it make a difference? I'm inclined to leave it empty.

I fill my s.s. water tanks (2 x 100gals.) each spring and top-off as necessary. When I winterize the boat in the fall the tanks are emptied.

~ ~ _/) ~ ~ MJH

[S/V Illusion]

Originally Posted by flightlead404

Newbie 1 week into boat ownership.

I'm leaving the boat for a week in Ft. Pierce.

Fresh water tank just emptied. I have the option of leaving it empty until I return and filling it then, or filling now and letting it stand.

I use a 2-stage 20 and 5 micron filter household (10") water filter to filter incoming water.

Does it make a difference? I'm inclined to leave it empty.

You are kidding, right?

[Scrimshaw4]

I ight be wrong about this but doesn't mold need air to grow? That's why I leave mine full. (Air gets in thru the vent) I find that a table spoon of baking soda helps keep the water tasting fresh. FYI I've been told a piece of copper in the tank also kills microbes.

[Joh.Ghurt]

Originally Posted by Scrimshaw4

I ight be wrong about this but doesn't mold need air to grow? That's why I leave mine full. (Air gets in thru the vent) I find that a table spoon of baking soda helps keep the water tasting fresh. FYI I've been told a piece of copper in the tank also kills microbes.

True, but full water tanks get all slimy on the walls under the water-line. If the waterline is low, the tank above has a chance to dry out and you'll have less to clean.

Also water gets stale over time and it's easier to empty it before you leave than when you come back.

[rmlarson1098]

Originally Posted by flightlead404

Newbie 1 week into boat ownership.

I'm leaving the boat for a week in Ft. Pierce.

Fresh water tank just emptied. I have the option of leaving it empty until I return and filling it then, or filling now and letting it stand.

I use a 2-stage 20 and 5 micron filter household (10") water filter to filter incoming water.

Does it make a difference? I'm inclined to leave it empty.

If you empty it, you might consider leaving the fill cap open, or at least cracked, and securing it (so nothing crawls inside) with a piece of s.s. or aluminum screen and a hose clamp. Or similar.
I've been told that even a little bit of air movement helps prevent mildew/mold.
For whatever it's worth!

[MartinR]

In my opinion: empty or full

No need to overthink.

[sailcrazy]

We share the opposite view. We've long heard that mold needs air to grow. If you empty your tanks, then all the fittings and hoses are also moist but full of air-the perfect breeding ground. We leave our boat on the hard every hurricane season (in the tropics, no threat of freezing)-and we leave the water and fuel tanks full, trying to minimize that mold/etc growth (if the tank/lines/fittings are full of water, there is no free air there). Then, when we return and resplash, we pump out that water, refill and add a little bleach per tank, waste that load, and then fill for use. so far-no issues. IF....you can drain and dry your tanks, and hoses, and fittings easily....well, that may be a different situation. But we can't drain and dry, so we leave them full of water/fuel. So far, it seems to work well ( now some 22 years later!)