Hot Tub - Emergency Drinking Water

[H2O-Dog]

I am interested in managing my hot tub water so that it could be used as a source for drinking water in the event of an emergency or contamination of the municipal water supplies.

For sterilization I plan on using Pool Shock (Calcium Hypochlorite) as this is what FEMA recommends for sterilizing drinking water. The disadvantage that I see is that it breaks down fairly quickly

I am less sure how to handle Ph and alkalinity.

To raise Ph I was going to use Arm and Hammer Baking Soda (12 pound bag). I believe that should be safe.

I am even less certain about a safe method for lowering Ph. Vinegar is a possibility, but may leave the water with an odd odor and taste.

Alkalinity??? I have no idea.

Any suggestions or advise would be appreciated.

Thanks for your help.

[chem geek]

You should not use your spa, nor your pool, water for drinking water -- at least not if they are used (i.e. not just storage for water, but have people in the water at any time). It's not so much about sanitation as it is about all of the undissolved organics and disinfection by-products that are in the water, as well as the fairly high salt levels.

If you have a hot water heater, then that is the best source for emergency drinking water.

If you absolutely have no other source of water available, then non-SWG pool water would be better than spa water due to the much lower bather load in the pool, assuming some reasonable regular water dilution (say from rain overflow or regular backwashing). If you have an SWG pool, then do not drink that water as the 3000 ppm salt level is high, though again if there is NO other source it's still better than no water at all.

[H2O-Dog]

Chem Geek -

To clarify: I have no swimming pool, just the hot tub. Water heater is tankless so no help there. There is no salt water system, but it does have an ozenator type system. Temperature is kept at 80 to reduce cost, discourage swimmers, and reduce growth of nasties. No one uses the hot tub at all. It is basically patio eye candy that came with the house. I thought it might as well serve a purpose.

I think hydrochloric acid should also work, but not sure where to get food or pharmaceutical grade low molar.

Or maybe I should just use the vinegar.

Thoughts?

[waterbear]

IMHO, you would be better off just stockpiling gallon jugs of water in your garage than using the hot tub for water storage.

[H2O-Dog]

IMHO, you would be better off just stockpiling gallon jugs of water in your garage then using the hot tub for water storage.

I agree that purified bottled water is better and I have a few bottles - 5 gallon though. But when it comes to water and emergencies, you never have enough. And 350 gallons is a lot of water to not be able to use.

[chem geek]

I agree with waterbear. Storing jugs of water would be better.

As for your hot tub water, I'm not sure why you are worried about pH and TA for drinking since maintaining the tub water would have those parameters be fine as far as drinking water was concerned. If you fill the tub with tap water and keep it chlorinated and don't use the tub, then it's probably in good shape, but if you just have it out there as "eye candy" then odds are you may not be keeping it sanitary and with warmer water pathogens can grow very quickly if you let the Free Chlorine (FC) level get to zero even for a short time (some number of hours). The ozonator will only kill pathogens that are free-floating and make it to the circulation system. It won't touch any bacteria growing in biofilms on surfaces, for example.

Muriatic Acid from the hardware store is pure enough to compensate for pH rise and not add anything bad to the water, but regular chlorination will increase the salt level over time. You should be able to get your TA level low enough (probably around 50 ppm) to stabilize the pH.

[quantumchromodynamics]

You could probably use a water treatment system to purify the water for drinking use. Perhaps a distiller or reverse osmosis system.

A treatment system would also allow you to use municipal water that has been contaminated.

[waterbear]

You could probably use a water treatment system to purify the water for drinking use. Perhaps a distiller or reverse osmosis system.

A treatment system would also allow you to use municipal water that has been contaminated.

This is assuming there is a source of power. As someone who has lived his whole life with hurricanes water is often potable way before electricity is restored.

[H2O-Dog]

Maybe I don't fully understand...

But I had thought it was a good idea to keep water chlorinated (or brominated which is not good for drinking) in order to kill micro-organisms and that in order to keep chlorine working well, that the PH should be a little below 7.5.

Running out of water is a bad idea, but drinking spa water that gives you dysentery isn't much better.

If I can maintain it properly then I have another possible resource to use in an emergency. Just trying to keep my options open.

[waterbear]

Maybe I don't fully understand...

But I had thought it was a good idea to keep water chlorinated (or brominated which is not good for drinking) in order to kill micro-organisms and that in order to keep chlorine working well, that the PH should be a little below 7.5.

Running out of water is a bad idea, but drinking spa water that gives you dysentery isn't much better.

If I can maintain it properly then I have another possible resource to use in an emergency. Just trying to keep my options open.

First, what is your soucre of chlorine? If you are using a stabilized chlorine (dichlor or trichlor) the the CYA present will make the effects of pH not that important in the grand scheme of things and also make the water unfit for drinking.

CYA acts as a "chlorine buffer" by forming chlorinated isocyanurates, which hold chlorine in reserve and also lower it's effectiveness as a sanitizer. However, the pH effect on the HOCl/OCl- rato (Hypochlorous acid/Hypochlorite ion) become negligable.

If you are using either sodium hypochlorite (liquid chlorine or laundry bleach) or calcium hypochlorite, which are the two forms of chlorine used for emergency water purification in addition to iodine) then the effects of pH do come into play somewhat. a pH of 7.5 or less is a good number to shoot.

Once again, I would not use this as potable water but it might be useful as water for bathing. I have gone through enough hurricanes to know that it is easy to stockpile enough gallon jugs of water to get through the emergency. Remember, your toilet tanks are also a good source of water and if you know some sort of disaster is coming you can also fill up your bathtub with water (Something my family had done ever since I can remember when we had a hurricane on the way).

Also consider that your hot tub is am exposed location so the water in it could (and most likely would) easily get contaminated in a disaster!

My suggestion is to start enjoying the hot tub by actually using it. You might find it to be addictive!

[quantumchromodynamics]

You could probably use a water treatment system to purify the water for drinking use. Perhaps a distiller or reverse osmosis system.

A treatment system would also allow you to use municipal water that has been contaminated.

This is assuming there is a source of power. As someone who has lived his whole life with hurricanes water is often potable way before electricity is restored.

A generator would be a good choice for people who want to be prepared for hurricanes and other emergencies.

[waterbear]

You could probably use a water treatment system to purify the water for drinking use. Perhaps a distiller or reverse osmosis system.

A treatment system would also allow you to use municipal water that has been contaminated.

This is assuming there is a source of power. As someone who has lived his whole life with hurricanes water is often potable way before electricity is restored.

A generator would be a good choice for people who want to be prepared for hurricanes and other emergencies.

I quite agree. However, having been in that situation i can tell you that it would be better used to keep the refrigerator running, lights, and (in florida at least) AC since hurricane season is summertime and it is very hot and humid here. If not AC then electric fans! Running a water purification unit would be very low on the list of my priorities. Then there is the problem of making sure there is enough fuel to run it. When the power is out you cannot pump gas at the gas station so you have to be careful on how you use what you have in your car and for your generator.