Fresh Water Tank, fill or not fill

[Rick and Michele]

My wife and I will be full timing in our Class C at an RV resort with full hook ups. Our question to the group is how often should we cycle water through the fresh water tank? We will be on the city hookup most of the days and only off it on trips away and when we want to exercise our rig by taking it out for a spin.  I was thinking of leaving it dry but I do not think this is a good idea. 

 

 

[Chad Heiser]

I only put water in my tank when I am going to use it.  I am still working full time so the rig doesn’t get used as much as I would like.  I have never had an issue with my water tanks on four different rigs over 20 years or so so far doing this.

[Chalkie]

We always keep some water in the fresh tank. For example, the park we are in currently just had a water emergency and had to shut down water for a while. At least we had water to flush the toilet. And when traveling, it is nice to have water for flushing the toilet as road side stops and gas stations don't often have cleanest of facilities.

[Rick and Michele]

10 minutes ago, Chalkie said:

We always keep some water in the fresh tank. For example, the park we are in currently just had a water emergency and had to shut down water for a while. At least we had water to flush the toilet. And when traveling, it is nice to have water for flushing the toilet as road side stops and gas stations don't often have cleanest of facilities.

Do you use anything in the tank to stop growth?  I know that before first use we will flush with a bleach mixture but after that is there a product that you use?

 

[agesilaus]

We usually keep it near full, but we boondock when we can. But you should keep enough in it when you travel so that you can stop along the way and make something to eat and use restroom. Also during a freeze you should disconnect the water hose and drain it and go on the water pump/tank while the temps are below 32.

[Rick and Michele]

21 minutes ago, Chad Heiser said:

I only put water in my tank when I am going to use it.  I am still working full time so the rig doesn’t get used as much as I would like.  I have never had an issue with my water tanks on four different rigs over 20 years or so so far doing this.

I am also working full time. Our plan is to move the rig once a month, when we can, and then to use the fresh water tank at that time. 

Thanks for the input.

 

[jcussen]

Never leave mine hooked up to shore water. Fill the tank and use coach water pump till 1/4, fill again and start over. Had a buddy on shore water, that left for the day, and came back to coach will water coming out from all sides of the coach and a small lake under the coach. Pex fitting came loose under sink. I turn my water pump on when I need water, and off when I don't need it.

[Rick and Michele]

17 minutes ago, agesilaus said:

We usually keep it near full, but we boondock when we can. But you should keep enough in it when you travel so that you can stop along the way and make something to eat and use restroom. Also during a freeze you should disconnect the water hose and drain it and go on the water pump/tank while the temps are below 32.

Thanks. We have a really nice self regulated water hose for the winter months. I also have a self regulating heat trace connection for the water hookup. All the tanks have heat pads on them so hoping that will help as well.

[Rick and Michele]

10 minutes ago, jcussen said:

Never leave mine hooked up to shore water. Fill the tank and use coach water pump till 1/4, fill again and start over. Had a buddy on shore water, that left for the day, and came back to coach will water coming out from all sides of the coach and a small lake under the coach. Pex fitting came loose under sink. I turn my water pump on when I need water, and off when I don't need it.

Wow that sucks but thanks for the insight.

[Kirk W]

We alway keep at least 10 gallons or so in the tank, just in case something should happen to the water supply. I use it out of the tank to nearly empty about once each month. If you sanitize the water system annually, you should be fine that way as we have been doing that for about 20 years now. I don't add anything special to the fresh water tank, just cycle the water out monthly. 

[Ray,IN]

On the sanitation side,  your tank is never completely empty unless the drain is in the bottom of the tank instead of in the sidewall as most are usually plumbed.

I have always kept our fresh water tank full and treated with chlorine to prevent bacteria unless the RV was winterized. I remember some years ago the RV resort had a water line break, no city water for 2 days, but we could not know how long the outage would last.

I did as Kirk detailed, use tank water once in a while to keep it fresh.I have kept tank water for 3 months at a time without any  negative effects when it was properly treated.

Edited November 2, 2020 by Ray,IN

[sandsys]

Even when in a park with full hookups we always used the water from our tank except the one time we had neighbors who were parked too close who complained about the noise of our pump. We'd just fill the fresh water tank every time we dumped our waste tanks. Like others mentioned, we were glad that was our habit when a park had a break in a water main shutting off everyone's water.

Linda

[lappir]

I keep the fresh water full all the time unless I'm getting ready to move. In the winter I fill the tank, empty it and refill In the summer I sometimes just keep it full. I use vinegar for sanitation every 6 months or so when I move. I don't often use it for drinking water, but most likely could without issues. Have had multiple locations with water that wasn't too palatable unless it was used to make coffee or cook with. My drinking water is most often sourced from one of the water dispensers with the 39Cents per gallon markers, but found a place this weekend for 0.22. 

A full tank takes a lot of cold weather to freeze, a hose on the ground too, but the section that's suspended in the air will freeze very quickly especially if there is not water running though it. Most parks where it infrequently gets to freezing suggest keeping a tap open to prevent freezing during the cold spells. I'd rather just fill my tank and not have to worry. 

 

Rod 

[Chalkie]

5 hours ago, Rick and Michele said:

Do you use anything in the tank to stop growth?  I know that before first use we will flush with a bleach mixture but after that is there a product that you use?

No, I periodically add some bleach. Note: DO NOT use the splash-less bleach. If the gauge on our tank says 1/3 full, I use 1/2 cups bleach. However, if we have filled the tank with chlorinated water from a city source or RV park that chlorinates water from a well I am not too concerned as algae needs light and the tank is in the dark. 

[RandyA]

Our experience goes like this:

Our water source at home is from a deep well.  It is truly "raw" water with no chemicals added.  Water from the well left in the fresh water tank in  hot weather goes bad (slimy, smelly or bad tasting) fairly quick - like maybe a week or less.

Water from a municipal water supply is treated with chemicals like chlorine, fluoride and who knows what else.  Municipal water stays usable for a longer period of time  (often a month or more).

Now, the question is - when at a campground - where does the water come from?  If you want to be sure it is OK you can add regular, unscented bleach (read the label for % of Sodium Hypochlorite ) so you end up with the acceptable 5 ppm chlorine to well water or even municipal treated water as follows:  (Note - adding these small amounts of Sodium Hypochlorite to municipal water will not harm you.  But, if you smell a strong chlorine odor from your municipal water with or without the added chlorine it is best to stop additional treatment.)  As you may know, you can run chlorine treated water through a carbon block filter to remove the chlorine (bleach) taste and odor.

For your convenience - one teaspoon is equal to about 5 cc.  It is much easier to add bleach with a syringe than a teaspoon.

Bleach containing 5.25% Sodium Hypochlorite

5 Gallons water, 1/2 teaspoon bleach

10 Gallons water, 3/4 teaspoon bleach

50 Gallons water, 4 teaspoons bleach

Bleach containing 8.25% Sodium Hypochlorite

5 Gallons water, 1/4 teaspoon bleach

10 Gallons water, 1/2 teaspoon bleach

50 Gallons water, 2-1/2 teaspoons bleach

This "formula" will keep your fresh water tank clean and stored water drinkable for as long as one month.  Keeping a few gallons of treated water in your tank to slosh around and flush the potty when needed with this mixture will also mean you do not need to "shock" your water tank with a stronger solution of bleach but once a season.

[agesilaus]

Quote

Our water source at home is from a deep well.  It is truly "raw" water with no chemicals added.  Water from the well left in the fresh water tank in  hot weather goes bad (slimy, smelly or bad tasting) fairly quick - like maybe a week or less.

Not our water, it can sit in the tank for months and be fine. I would be concerned about the quality of your well water, maybe take a sample to you local health dept. Of course our well water is the same Floridan aquifer water that gets bottled and sold all over the country.

Unless there are contaminants in the water, nutrients, nothing will grow in the dark tank.

[dogyard]

I've used Purogene ever since I saw this video from Escapade - 

When I did further research I found it was used by many boaters. Works very well for us and seems much safer than chlorine solutions.  

[Rick and Michele]

Thanks all for the comments. I appreciate each and everyone.

 

[RandyA]

10 hours ago, agesilaus said:

Not our water, it can sit in the tank for months and be fine. I would be concerned about the quality of your well water, maybe take a sample to you local health dept. Of course our well water is the same Floridan aquifer water that gets bottled and sold all over the country.

Unless there are contaminants in the water, nutrients, nothing will grow in the dark tank.

It is not uncommon for "raw" water to contain tiny organisms that WILL grow in the dark.  These come from the soil and rock in the aquifer the water flows through.  These organisms are harmless to the human body but can cause water from the source that is exposed to oxygen to develop a bad taste or slimy surface over time.  Our well water comes from an aquifer over 500 feet down in limestone and has tested as free of any harmful bacteria.  We have been drinking it for 23 years and are still here.  This is normal for raw water from any natural source. Most bottled water is purified through RO from a municipal source with minerals added back or treated "as is" with UV light to kill any such bacteria.  If your experience is different that is great.  But my experience indicates caution if storing raw water in a RV tank during HOT weather for extended periods of time.  Add a measured amount of Sodium Hypochlorite for safety.  My information comes directly from a friend that has a PhD in chemistry and is the Chief Director of a water treatment facility.  I have trusted his advice for RV water for decades.

[agesilaus]

Quote

RV tank during HOT weather for extended periods of time. 

Gee do you have hotter weather than Florida in summer? And summer in FL runs from April thru November. Any organism requires certain elements, usually abbreviated as CHONSP plus trace elements. And the energy source, usually sunlight but can be chemical energy in anaerobic organisms. My tanks are lacking most of those.

[RandyA]

21 hours ago, agesilaus said:

Gee do you have hotter weather than Florida in summer? And summer in FL runs from April thru November.

Pretty close 🤕. We spend December through March in Melbourne.  I like the weather during those months.  We live in what is known as the "Tidewater" of VA.  Upper 90's to low 100's plus unbearable humidity are not unusual here in July and August.  Not Arizona, but it does get hot.  We come home in the summer to let our doctors and dentists fix everything so we can come to your state in the winter.  I am making no argument - only reporting what I have observed and learned.  The center of the entire conversation and question was if cycling water in the tanks was needed or to just keep them dry.  My response was to shoot for 5 ppm of chlorine easily obtained from regular bleach to keep everything sanitary.  Heading your way soon (I hope).

[agesilaus]

Heh, it's sounds about the same. We had a taste of your weather on a visit to DC years ago. Boston was just as bad if not worse.

Standard target concentration of Chlorine is 1 ppm unless you are superchlorinating to sterilize a contaminated tank or piping when it would be much higher. You would not want to drink water at 5 ppm but it would not hurt you, just taste awful.

I was licensed as a water system operator but only at the lowest level for the small system we ran at where I worked.

Edited November 5, 2020 by agesilaus