Potable Water on RIvers

When you are on an extended river trip that would be too impractical to carry all your drinking water, what do you do? Is filtered water still safe to drink on these rivers? I am concerned particuarly about drinking chemical pollutants.


Also, some western rivers have salt
in them and can’t be used.

On the chemical issue, sometimes you can get information from the managing agency or from state DNR. You can also go to the USGS site for satellite gauges and find some data on stream contents.

One way to watch for pollutants is to check a river on Google Earth and see what is upstream. Topographical maps may show old mining sites.

Googling for trip accounts from others who have done the trip you are planning may show what they did about water.

In '73 when we were in Quetico, everyone was still dipping water out of the lakes and drinking it. I think now most would choose to filter. When a group of us ran the San Juan in '99, a support raft carried all the water. The river was so silty is would have clogged filters too quickly. When I ran part of the Dolores in '05, I carried all my water in water bottles because there were too few side streams, and the Dolores is too salty because it runs over the heads of underground salt domes.

Most of the long wilderness trips I know of in North America have plenty of filterable water, either from the rivers or from side streams.

I did . . .
. . . a trip down the Mississippi last summer and gave that topic some thought and research. Turns out the river is much cleaner than the hype would lead you to believe. Most of cities/towns along the river use it as a source of drinking water, only removing silt and treating with chlorine.

I took a Katadyn pocket filter with me but it was a lot of work. I ended up just treating my drinking water with chlorine bleach and doin’ nothin’ but filter out some of the silt for the stuff I cooked with.

It depends on how long “extended” really is. if I’m not on a trip that requires portaging, why not carry my water, so long as I have enough room in the boat. Its easier and quicker than treating or pumping river water. Assuming one gallon a day per person though, that can add up to a lot of weight at 8 lbs/gal, and a lot of volume. So for trips of a few days, carrying all your water would be practical enough - a few weeks though, and unless you have a really big boat, you won’t have enough carrying capacity.

If you are concerned about filtering, buy a “purifier” - they do a better job and clean up more stuff than a filter will. There probably isn’t a real effective way to remove all chemicals from the water though - treating with bleach is even adding one.

Good water tip
I carry a 2 gallon bucket on silty rivers, and fill it every evening. I filter my water from it in the morning, by then the silt has settled. As far as chemicals, farm runoff is probably the worst.

To filter or not to filter
The decision to filter, treat, or carry all your water obviously depends on a whole range of factors. Are you kayaking or canoeing? I have yet to find a 16-18 foot canoe that can’t manage to carry enough water for two people for a week long trip. Kayaks are a totally different story with a capacity for a couple of days being max.

Assuming you just have to pump or treat your water source then other factors plug in to the equation:

l. Silt content in the water source.

2. Types of contaminants in the water source

3. Water temperature

There are two types of silt in water. Glacial Silt and Soil Silt. Glacial silt does not settle out of solution easily and is harder to eleviate. Soil Silt will settle out relatively quickly and is easier to strain out of the water source. Both types create problems. Soil Silt clogs all pumps fairly quickly. Glacial Silt takes more time to clog, but it also has a drastic effect on the digestive system if drunk in any quanity.

Pollutants, bacteria, and virus also are factors in water drinkability. Only one water filter on the market “First Need” is able to filter out all of the above. All of the others like MSR, Sweetwater, Pur, etc have limitations. Problem with “First Need” filters is they are the quickest to clog when used in silty water, and the whole filter has to be replaced at a high cost. All the others use combinations of ceramic, silver iodide, and carbon filters. They are much better in silty water and can be cleaned when they become clogged, but won’t take out pollutants or virus. All filters run from $59.-$250 depending on size and pumping capabilities. They weigh from 14 oz. to 2.5 pounds.

Using Tabs or Ultra Violet Sticks are other means of purifying as well as boiling water for twenty minutes. Problem is none of these methods is going to extract any of the silt in the water or take care of chemical pollutants.

I personally carry a filter, tabs, and a five gal plastic water carrier in my canoe when on extended trips on rivers like the Colorado or Missouri which are high silt content rivers. Usually you can find side tributaries where none silted water is available.

My personal favorite water pump is the old PUR Guide Water Filter. It pumps a higher volume of water than any of the current models put out by KAT, MSR, or Sweetwater, and its use of silver iodide and carbon filters in combination keeps the water good tasting.

If you choose to carry…
Check these out. www.boatabag.com They work great.

backpacker tip
carry some coffee filters and use one or two wrapped around your pump filter’s pickup screen, secured with a rubber band. it’ll act as a cheap and disposable prefilter and make your expensive filter go much longer without clogging.

An alternative to carrying and filtering
I will be doing a trip in northern VT that is mostly along the Missiquoi River which, despite its sparse residential development along it, is heavily impacted by farm runoff. Filtering or treatment is not practical or advisable due to the contaminents. It is also not practical to carry all of our water for the 7 day trip, since we have a number of portages along the route.

So, the plan is to carry enough water for a couple days and either refill the containers with the permission of landowners by using their faucets, or buy additional water in local general stores along the way. Fortunately there are enough towns at decent intervals that make this approach possible.


All good ideas. I was wondering what people do on longer trips. It is an interesting problem.

Why is agricultural runoff a deterrent
to filter use, especially when one is using a filter with a purifying silver component?

berkey water filters?

– Last Updated: Feb-03-10 7:49 AM EST –

Does anyone have any experience with Berkey water filters?


chemicals are in solution

– Last Updated: Feb-04-10 10:38 AM EST –

"Why is agricultural runoff a deterrent
Posted by: g2d on Feb-02-10 4:57 PM (EST)
to filter use, especially when one is using a filter with a purifying silver component? "

seems like the basic concept behind water treatment is to kill the little buggers, not to filter out chemiclas, though some of that may occor - charcoal probably "absorbs" or changes some chemiclas since carbon tends to bond to lots of other chemicals, and some filters have a charcoal filter element - not sure how silver works

but think about salt water - that is water with salts and other? chemicals in solution (lots of gold in seawater, just not cost effective to get it out) - I don't think there is a filter or purifier made that you can just pump some sea water thru and have nice clean tasting fresh water come out? is there? to get drinking water out of sea water, it has to run thru a desalinization plant of some kind, and I think that is more a process of boiling off the water into vapor, leaving the salts behind (but I don't know that for a fact)

edit - 2/4/09 - but what did Verlon Krueger or Freya Hoffmester do out in the ocean for water - maybe that's the answer to filtering chemicals

Agri runoff
See Matt’s reply below regarding farm chemicals, many of which will not be filtered out by most (any?) filters, nor be removed by boiling.

Also, thanks to a lot of cows, pathogens and bacteria (e-coli etc.) are present throughout may rivers flowing through dairy country; again, filters will not remove these bacteria.


Actually, the best filters completely
solve the bacterial and virus problems. Smaller molecule chemicals may be another issue, though I wonder whether the Dept of Agriculture, EPA, etc, are allowing substances to be sprayed on fields which persist in runoff entering streams.

Remember, towns and cities have to remove all contaminants for water supply. It seems unlikely that substances which can’t be removed by charcoal filtering would be allowed for agricultural use.

But seriously… don’t worry about bacteria. Good filters remove them.

I’ve noted before that some western
rivers run through salt domes, and are too salty to be used for drinking water unless distilled. When I ran the salty Dolores, I had no reasonable choice but to carry water. But no segment of the Dolores is likely to take more than three days, and fresh water can be obtained where the river breaks out of one canyon before entering another.

I think that in North America, there are very few rivers where one can’t obtain safe water by filtering what is available in the river itself, or in side streams.

Agriculture enjoys many exemptions
Often, more exemptions than are allowed commercial development. After all, they’re just farmers who love the environment. Unfortunately, it is a fact that in many areas, agriculture has done more to harm water quality than most other land uses. Depending on where you live, of course.

I’ll have to check into filters a little more, but I know mine has a charcoal filter and I’m pretty sure that it contains a warning that it is not effective for e-coli.


I use an MSR Sweetwater
and e. coli is one of the things it’s advertised as removing. they say it meets the EPA standard of “removing 99.9% of protozoa and removing 99.9999% of bacteria” as well as reducing chemicals/toxins and pesticides. if viruses are a concern (in 3rd-world countries or other areas where contamination by human waste is an issue), supplemental treatment such as iodine is wise.

some good faq:


Even the old PUR Hiker I used to use
said it removed all bacteria including e coli. It’s a good thing, because e coli can be in mountain streams from human feces and other sources. Viruses call for a little better filter, but there are plenty such on the market now.

Settling muddy waters…
You can also sprinkle alum (aluminum sulfate) on top of a pail of muddy water to remove suspended solids. Doesn’t take much; just like salting a hamburger. Allow to settle overnight. Decant or siphon off gently. This clear water can be treated with chlorine, then used for washing dishes, etc. This way you only have to carry water for drinking. We did this last year on a four day trip on the Rio Grande.

As mentioned this does not remove dissolved salts. There are emergency desalting kits required for aircraft flying over seas that could be used to remove these salts. These kits use either an ion exchange packet, an osmotic membrane and syrup, or a pump. The pumps are expensive ($800) and low output, no more than one quart per hour. This is okay for survival, but not for a small group of thirsty paddlers. I haven’t found a source for the packets, but would like to know if anyone knows or finds a source.

As for the agriculture chemicals, an activated charcoal filter would help remove these.