Sanitizing Water Tank

[Kirk W]

 

I'm not sure how anything airborne would get into the system. There's a screen on the vent, a cap on the hose fill, and those are behind a locked door.

There is air in your fresh water tank, via the vent and the overflow, moving in and out as you fill and empty it. While the screens will prevent large things from entering, spores of mold, algae, and such are microscopic as are the bacteria and such. There is also usually an air bubble at the top of most water heaters. If it works for you that is great, I'll stay with the health folks who suggest sanitizing. But I don't use an RO system either, just a carbon block filter.

[Big Z]

There is air in your fresh water tank, via the vent and the overflow, moving in and out as you fill and empty it. While the screens will prevent large things from entering, spores of mold, algae, and such are microscopic as are the bacteria and such. There is also usually an air bubble at the top of most water heaters. If it works for you that is great, I'll stay with the health folks who suggest sanitizing. But I don't use an RO system either, just a carbon block filter.

 

I think it has, worked for us...I'm at a point with the MH that sanitizing has crossed my mind more than a few times! Like I said, continuous use has probably been the key for us. As soon as the float switch in the tank drops, were making H2O!...from the spigot to a three filter manifold, 5 micron... 1 micron... and carbon filter... then an 80# pressure pump pushes it through 2 RO membranes and topping off the tank. The water we drink from the kitchen is filtered one more time with a solid block charcoal filter which replaced the ADC under the sink.... We drink in excess of 2 gallons of water per day, make lots of ice, a couple showers, use RO for washing machine, and, and, just used the chit out it!

Anyway!... as the MH has been idle for a month er so now and were getting set up in the 5th wheel, I will be going through it and sanitizing the system for sure!

 

ps. I had the RO system set up and in the 5th wheel before it's first full tank!

[Jack Mayer]

Kirk, I also use a whole house RO system.

 

To solve your issue - which CAN be an legitimate concern - I intend to put a UV light on the line feeding the kitchen area (and refrigerator). This will kill any of the nasties than may spawn in the fresh water tank. But that tank gets "turned" pretty regular - we average 20 gallons a day. So it does not sit long. Nevertheless, things could still breed in there. SO the UV light will get the drinking and cooking water on the way OUT of the fresh tank. I could do the entire outfeed of the tank, but I think just the kitchen will suffice.

 

The downside of that is that the light is used all the time....eg. I can't just purify the water and put it into the tank. (Well I COULD, but it would then be sitting in air exposure until used.) Thus - with the light in constant "on" for our water in the kitchen - it is not conducive to a boondock situation. Even with my solar setup. I may put one on the "input" to the tank as well as the "output". That would solve the issue, since I would only purify the water going into the tank, but it really is not the best strategy. The bottom line for boondocking is we don't use the RO system. It does go through three filters, though.

[skp51443]

Since the RO units don't fill the tank as fast as using city water would a fine particulate filter in the air vent line do any good to prevent stuff from being sucked into the tank when you draw water out of it?

 

Like this Amazon mini filter or one of the larger sizes if you think this 1 micron unit wouldn't flow enough?

[Kirk W]

Jack, why couldn't you devise a way to make that light operate as the tank-less water heaters do, only turn one when in use? Would that be enough time for the light to do it's job?

 

Some of the algae that grow in fresh water systems can be funny as there are those which will grow in chlorinated water, or so I have been told. I know that some grow in hot water of the water heater and those can be the worst to get rid of. I guess I don't know that they come from air contamination, but suspect that it is where they originate and I know that it can be a source of it.

[Jack Mayer]

Yes, Kirk, that would work and could be done. The sanitizing effect is instant as the water proceeds through the pipe with the light built around it.

[jpatrickc]

We had a UV light at a previous house that had a well. We were told that if the light is turned off you need to re-sanitize the whole system. The nasties can move thru the water to the other side ( output) of the filter. It depends on the light being on continuously to prevent the bad stuff from getting from the input to the output just by swimming thru the pipe even without water flow. It makes sense to me.

 

Pat

[Kirk W]

It depends on the light being on continuously to prevent the bad stuff from getting from the input to the output just by swimming thru the pipe even without water flow. It makes sense to me.

I never thought of that, but it does seem logical.

[reed and elaine]

How much power do these UV sanitizing lights draw and who are the manufacturers? This might be something we should want to install.

Reed and Elaine

[Barbaraok]

Again, how or why? The tanks are there to be used. Why would you ever leave them empty or low? Whether in a full hookup CG or dry camping, I have my tanks in full use and my water pumps on and working (for best water pressure and flow). I just can't figure out why anyone would do anything else.

 

100 gallons of water is 800+ pounds - weight that we don't want to carry down the road. We don't routinely boondock, so really never have full tanks going down the road. When at a park with city water, why use the tank - much easier just to turn on the faucet hooked up to city water. Plus we have gone through several ShurFlo pumps so you get to where you really don't want to depend upon something that is going to stop working without any notice. We are now using an Aquajet pump, seems more reliable. The other reason we don't use a pump is the onboard washer/dryer, much easier being hooked up to city water.

 

Barb

[Zulu]

We had a UV light at a previous house that had a well. We were told that if the light is turned off you need to re-sanitize the whole system. The nasties can move thru the water to the other side ( output) of the filter. It depends on the light being on continuously to prevent the bad stuff from getting from the input to the output just by swimming thru the pipe even without water flow. It makes sense to me.

 

Not me -- unless you kept the UV off for months. It sounds like a way to sell UV bulbs.

[Zulu]

How much power do these UV sanitizing lights draw and who are the manufacturers? This might be something we should want to install.

 

I went with a Sterilight Cobalt SCM-200. It's a pricey 110V unit, but I wanted a UV filter with a high flow rate (6 gpm) and a meter to monitor the UV light intensity.

 

The RV Water Filter Store sells 12V (and 110V) UV filters, but they are low flow (2-3 gpm) units. To me, that's too low. Before I bought my UV system, I bought a flow meter and measured flow rates at several places I camped. In most cases flow rates were > 2-3 gpm.

 

UV filters have calibrated flow rates in order to insure appropriate "dwell time" -- the amount of time the water is exposed to the UV light. If you exceed the dwell time, then there's no UV sterilization.

 

However, Sterilight does make a 12V 6 gpm system, but it doesn't have a light meter.

[lappir]

These light things seem expensive. Do the units limit the flow rate or do you have to install a limiter before the light?

 

Rod

[jpatrickc]

Not me -- unless you kept the UV off for months. It sounds like a way to sell UV bulbs.

The part that made sense to me was that if you turned off the UV light for even a minute the pathogens could pass thru the area where they would normally be killed. At this point your water supply has been compromised. I don't think a UV Based system is a good option for an RV. The bulbs were expensive also. Back in the time (1990's) they were $60-$80 and lasted 12 - 18 months.

[Jack Mayer]

Why do you not think a UV system is not good for an RV? If it is good for a house, it would be good for an RV under similar circumstances. I'm not claiming that a UV light is "necessary" for an RV - any more than it is for a house. But I don't know what about an RV disqualifies it from using one.

 

Three gallons per minute is around right for an RV pump in normal use.....but you would want to be sure you have enough flow rate.

 

The lights are not cheap but they are not incredibly expensive, either.

[jpatrickc]

If you are a full timer and can run it from 12 volts or from an inverter then I guess it would be OK.

The fact that it depends on the light being on continuously to provide protection makes me say that it is not the right solution for an RV. The instructions I had said if the power is off you should go through the same sanitization process that you use when you first install the system. I guess if you are at a location with shore power it would be OK, but it seems like there should be a better solution.

[Alie&Jim's Carrilite]

My opinion-

Depending on how you RV, the light either makes sense and is a great addition to your water purifing capability, or it's a neat gizmo you can have to impress other folks at the city water supplied campground.

In Jack's instance, since they build a coach with the intent of selling it in the near future, they outfit the coach so it can be a great boondocking rig or a resort queen or anything in between.

Have the RO system and the UV light will pretty much guarantee safe water wherever you go and whatever water source you use.

But you have to be willing to pay the $$$ price and use your own water tank all the time, which means having an above average water pump and possible a backup.

Having been in some "Resort" campgrounds when they have a water line break, or the city decides to flush the lines and breaks all the crude loose inside, having the means to filter and/or purify your water comes in pretty handy. As everyone that has moved around the country knows, the water quality from region to region varies greatly as well.

Our personal filter system is a 3 filter system that has a 2mic filter, sterasyl ceramic, then a carbon block. and we still don't drink the water from the tank that's delivered to us (semi boondockers on an oil rig site) because of the sanitary issues of how the water is handled before it reaches us.

Putting a UV light in line would make the water drinkable and we know of several people that do this exclusively and drink the water that's delivered with no issues in over 5 years. If we could "afford" the water waste, I'd have an RO system plumbed in with the UV light and never worry about any water borne issues again.

For cleaning our water tank, I over chlorinate (using pool tablets) our 250 gallon supply tank and pump it into our onboard tank bypassing the carbon filter and open the faucets to get the the chlorinated water thru the system. Shut it off and let it sit for several hours, drain the fresh water tanks and our 250gallon supply tank, and refill with our filtered water. We do this quarterly as our water delivery permits.

Lastely, as a kid I drank water from sources that today would be discouraged. The garden hose that was outside all winter, the faucet right off the water pump. And then my grandparents hand water pump (yes, you actually had to pump it to get water up) that was full of iron, but cold and good tasting, and yet I'm still here.....

[Wrknrvr]

If using a UV light one should replace the bulb as required for that specific unit. Also one needs to clean the glass tube the light is in as needed. it may get covered in physical particles from the source, a chemical deposit from the source or a grow algae on it. Any thing that will not pass the proper amount of light will render it ineffective. if the light is off at all the system needs to be treated to be effective again.

I installed them while I had a well drilling business. If there was a problem that was not practical or cost effective to correct then that was a solution. Dairy farmers sometimes needed them and the milk inspectors would drop in and include the record of the UV light and upkeep for there operation.

 

Vern

[Jack Mayer]

I think Jim (post 2 above) has a pretty good handle on the water issue. You can drink most "city" or "park" water and never have any ill effects. You can store it in your tank and use it and drink it most of the time with no ill effect. So how lucky do you feel?

 

We SPECIFICALLY prefer an RO system because we have found that we get consistent drinkable water that does not ruin our fittings, and keeps everything cleaner. And it wastes water, although that can be minimized. But it STILL wastes water. It would not work in Jim's situation since they are running off of trucked-in water. In his case I'd just be using filters, too. And probably a UV light on it - since he has unlimited power and a water system that is more prone to contamination. In the grand scheme of things the cost is not great.

 

Our system is designed to operate either way - RO or conventionally. It may not be the best implementation of RO, since it requires the fresh tank for storage. Someone here has added a large RO tank separate from the fresh tank. That has some advantages. I may do that next time. It would allow me to "make" (lets say) 40 gallons of RO, UV it at the "making" and then use it on demand without running the UV light all the time. There would be "some" vulnerability, but not much. I'm not sure which is better. But for now, I like the RO system we have. And we would not be without RO water in the future - unless we are boondocking where it is not practical.

[Zulu]

The part that made sense to me was that if you turned off the UV light for even a minute the pathogens could pass thru the area where they would normally be killed. At this point your water supply has been compromised.

 

True, if water could move through the filter when the UV light was off, but not so when both UV and the water are off. For example . . .

 

Option 1: Using Water Holding Tank -- My RV system is plumbed so that incoming water always go through my filtration system. Typically, I'll turn my UV light on, fill my water tank, then turn UV off. Then I draw water from my water tank -- which does not go through the filtration system again.

 

Option 2: Using On Demand -- On the other hand, I can switch to an "on demand" mode in which water bypasses the water tank an goes right into the RV. In this case water always goes through the filtration system and my UV light is also always on.

 

House water systems are almost always Option 2 (On Demand) because there is no water holding tank. Water keeps flowing even with the power off so there would be a need to re-sanitize your water system. However, not so with Option 1.

 

 

[Zulu]

If using a UV light one should replace the bulb as required for that specific unit. Also one needs to clean the glass tube the light is in as needed. it may get covered in physical particles from the source, a chemical deposit from the source or a grow algae on it. Any thing that will not pass the proper amount of light will render it ineffective. if the light is off at all the system needs to be treated to be effective again.

 

First, that's why UV filters should be at the "end" of the filtration line so only the cleanest water goes in. BTW, that's why I chose large, clear plastic sediment & carbon filters in my setup, so I can see if the UV pre-filters are getting fouled.

 

Second, that's why I bought a "controller" for my UV filter which monitors the following:

• Visual "Power-On"
• Audible Lamp Failure Alert
• Lamp Replacement Reminder
• Visual Lamp Life Remaining
• Total Running Time Displayed

Finally, while the principle may be the same, I don't think a comparison between UV filter use in well drilling/dairy farming and UV filter use in RVs is altogether valid.

[Zulu]

If we could "afford" the water waste, I'd have an RO system plumbed in with the UV light and never worry about any water borne issues again.

 

If you don't use a whole house (RV) setup like Jack, then just plumb the RO waste water back into the water holding tank (which, I assume, you would no longer drink from because of your RO system). No water waste.

[Alie&Jim's Carrilite]

 

If you don't use a whole house (RV) setup like Jack, then just plumb the RO waste water back into the water holding tank (which, I assume, you would no longer drink from because of your RO system). No water waste.

Sooner or later though I'd have a tank of brine water. Then what? Since we are only on hook-ups every 4-5 months at best, I'd be dumping salt water on some ranchers land. As picky as some of them are, I don't want to go there.

[Jack Mayer]

Jim, you would just use that water for showers and toilet.....

[Zulu]

If you don't use a whole house (RV) setup like Jack, then just plumb the RO waste water back into the water holding tank (which, I assume, you would no longer drink from because of your RO system). No water waste.

 

Sooner or later though I'd have a tank of brine water. Then what? Since we are only on hook-ups every 4-5 months at best, I'd be dumping salt water on some ranchers land. As picky as some of them are, I don't want to go there.

 

Here are my TDS (Total Dissolved Solids) readings for Lake Havasu City, AZ:

• Untreated tap water = 697 ppm (incredibly hard)
• RO treated water = 24 ppm
• RO waste water = 724 ppm

To me, there's not a significant amount of difference, but your water holding tank salinity would certainly increase. That's why the tank is for washing, not drinking.