Potable Water Filtration

[mike baker]

I would like to install a water filter for the potable water because we don’t feel comfortable drinking water from our storage tanks without some type of filtration.   All water would be filtering since we rarely use the shower (we use a lot of deodorant instead).  We boat exclusively on Lake Erie (may venture to other lakes soon) and our sources of water are usually safe.  The intent is mainly to filter out the critters that might grow in the tanks.
 
I would like to get good filtration (down to 1 micron, if possible) but know very little about the subject.  One concern is pressure drop â€" will the water pump (factory issue) be able to push the water through a good filter at a reasonable volume?  Also, what type of filter media should be used -- the catalogs offer several different types.  

The mail order catalogs offer filters ranging in price from $20 to $400, but give very little data.  Has anyone else done this?  Can you give me some pointers?

Mike Baker #815 "Gray Hawk"

[Jeff Tancock]

I may be able to help you as I went through this last year. After finding critters growing in my forward tank it was uncomfortable drinking straight from the tank. I installed a 1/2 size household "filterless cartridge" (Ametek - about 6" tall) under the galley counter in line after the pump. Inside that I installed a 0.5 micron carbon filter cartridge that would take out everything including the bleach that I would add to the water during fill up. I found that although the pump could handle it, it seemed like the pump was under stress and the flow diminshed somewhat. I didn't want to burn out the pump so I then switched to a 5 micron cartridge to just take out the "chlorine, fine sediment, bad tastes and odors". The pump handles this cartridge better, but I tended to overchlorinate and my wife could still notice the bleach. Now I have just purchased a second cartridge holder and put on the appropriate fittings so that I will use the 0.5 micron filter cartridge on the hose when filling to remove everything incuding the critters, use a very small amount of bleach then have the 5 micron filter in line to remove any residual chlorine and bad taste. I believe that this will be a good and inexpensive system for safe drinking water. If you have any specific questions, just email me.
Jeff

[hdevera]

I know you must have thought about faucet filters such as Brita (which I use).  I find that adding using each tank until it is empty and adding clorine to the water when I fill it keeps growth in the tanks from being a problem.  I use the faucet filter to take out the clorine taste and odor.  I find that the filter does slow the  water flow from the sink faucet but I have not found this to be an irritation.  

The plus side is that it is extremely easy to change the filters and at least with Brita, there is a dummy light to remind me.

[kenkillian]

As Hal suggested, we use a filter atttahed to the faucet (Brita) and it works great; easy to change, bypass if needed, and eliminates bad taste and critters.  We still have the primary filter on the water, but we no longer worry about the water.

[Ray & Sandy Erps]

I went down to the boat today to drain all the fresh water because we have a week of cold weather on the way.   While I was at it, I pulled out the "in-line" carbon filter that's rated for sediment, chlorine and odors.  I've been putting it off, because I haven't seen a direct replacement at Westmarine.  The filter is a "systems IV" filter, totally enclosed with a 1/4 pipe thread on each end.  I took it to the local hardware store "Lowes" and they sold a similar replacement cartridge put out by "Whirlpool" as an "in-line refrigerator filter".  It was only $9 compared to similar products for over $20 at Westmarine.  They also had one that was good for cysts that was under $20.  I couldn't find a micron specification on the package but it might be worth checking out as a more reasonable alternative to water filtration.

[Ron Hill]

Mike : I filter the water as I'm filling the tanks and I also have a filter on the galley faucet.  The filtering on the filling gets rid of any impurities from well water.  A thought.  

[SailDan]

We use the faucet type filter with the activated charcoal cartridge.  The filter can be by-passed by flipped housing to one side. (See picture of filter on the Sink Cover / Cutting Board project on this site.) This is important since we never run hot water through the filter. We change the cartridge at least once a season. These are  relatively inexpensive filters and, in our experience, do a good job removing the chlorine and other undesirable "flavors" associated with boat-tank water. However, flow through the filter is slow.

[Ken Juul]

Last season I added an inline charcol filter after the pump before the lines spilt for the hot water feed.  It is about the same size as the racor.  Think the whole unit cost about $20, replacement filters are about $6 at the local RV supply store.  No noticable change in water pressure, sure helps with the taste.

[Ron Hill]

Guys : The two drinking water filters I talked about are written up in the Mainsheet Tech notes with pictures.  In essence they are:
1. A PUR filter on the faucet
2. Another that is adapted to connect to a hose (AMERTEK) that fills the tank.  Lowes has them for $15.

Both have throw away charcoal carterages.  Both carterages are EASY to get to and change.  A thought.

[Mike and Joanne Stimmler]

I purchased a "whole house water filter" from Home Depot for about $15.00 , a 3 pack of filter cartridges  for about $10.00 and male and female hose fittings to screw into the in and out ports of the filter housing.

I also have a white RV type hose made for drinking water that I use EXCLUSIVELY for filling the water tanks and nothing else.

I am also careful to NEVER allow either end of the hose to touch the ground and after coiling the hose while draining the water out (it's good if you have a helper for this), I connect the ends together to keep any contamination out.

I follow Peggy's recommendation of cleaning the tank out once a year with a strong concentration of chlorine bleach followed with a good flushing with fresh water.

You also need to USE the water in the tanks so that it is constantly changed. That means you should use one tank until it's empty and then switch to the other tank by closing the empty tank valve first, then open the full tank valve. This keeps the full tank from draining into the empty tank.

If you are using city water to fill your tanks, you don't need to routinely add any chlorine to the tank each time you fill thus the tank will be self cleaning as ling as you continue to use and change the water.

The only charcoal filter I would use is the Brita type at the faucet itself and then only to help the taste if necessary.

My humble opinions but they work for me.

[Ron Hill]

The biggest problem that people have is not keeping the water moving!
With aft and starboard tanks it's easy.  Only draw water from the starboard tank.  When it is empty (spits) refill from the aft tank.  It fills from gravity as the aft tank is higher.  You have 2 refills from the aft tank until it's out of water!! 
I only ever fill the aft tank from a water supply and let it gravity feed the starboard tank. 
As mentioned if you use city water you don't need to add bleach.  If not one capfull of bleach will treat 25 gallons.  A thought   

[swatbolish]

@Ron Hill thanks for your tips.