3M Water Filters

[Maine_bill]

We own a 35 ft Pearson Sloop and to save space we are thinking of installing a 3M Water Filter for potable drinking water.
We would clean as best as possible one of our built in water tanks..Approx 20 gallons.
We were thinking of installing the 3M 3MDW301 Advanced Drinking Water System filter..
Just looking to see if people think this would produce safe (and good tasting) water to drink..

Thanks
Bill

[thinwater]

It's a bit more complicated than that.
1. Is the tank clean? This should be done every fall (clean and dry for the winter).
2. Is the intake water clean? Though I'm a big believer in the general safety of US tap water, marina hose and plumbing shed enough algae into the tank to make it a great breeding ground.
3. Is the water treated? Since any filter can by-pass a few bugs, there should always be some chlorine in the tank.
4. Is the vent filtered? Bugs can and do crawl in (plumbing code).
5. Is the filter NSF 53 rated to remove cysts? Some are. Which 3M filter? Many are just for particles and are rather useless.

Better systems, in my opinion, are based on universal parts, not proprietary single-source parts. Pentek and Filters Fast are a good source.

Tap Water that’s Better than Bottled - Practical Sailor Print Edition Article

[gordwedman]

Originally Posted by Maine_bill

We own a 35 ft Pearson Sloop and to save space we are thinking of installing a 3M Water Filter for potable drinking water.
We would clean as best as possible one of our built in water tanks..Approx 20 gallons.
We were thinking of installing the 3M 3MDW301 Advanced Drinking Water System filter..
Just looking to see if people think this would produce safe (and good tasting) water to drink..

Thanks
Bill

I have had the following 3M system in my boat for a couple of years:

3M 5616207 WV-B2 RV Whole Vehicle Filtration System

This unit plumbs into your main delivery line from the tank so water going to the hot water tank or the cold water faucet is filtered. I have taken one apart and there is a large pleated filter for particulate removal and quite a lot of charcoal for removal of chlorine and organic compounds that might produce taste and odour. I have a simple pleated particulate filter ahead of this filter to remove gross particulate matter. I am quite happy with the water from my 35 year old aluminum tanks.

If you fill your tanks from city water I don't think you need to be too concerned about microbiological contamination. You mainly want to remove paticulate matter from the tank and lines, maybe organic compounds as well. These filters should do a good job at that.

You don't mention if you have metal, plastic or fiberglass tanks. You say "built in" so I am guessing fiberglass. If this is the case the charcoal is worth having to remove objectionable taste.

[thinwater]

Originally Posted by gordwedman

...If you fill your tanks from city water I don't think you need to be too concerned about microbiological contamination. You mainly want to remove paticulate matter from the tank and lines, maybe organic compounds as well. These filters should do a good job at that....

Mostly true, but not quite. The city water should be safe from a human pathenogen standpoint, but that is not the same as saying it will not breed bacteria, weird smells, and tastes.

Unless the tank is kept clean of biomass and dirt, bacteria will grow in the dirt, even in the presence of some chlorine from the city water. The residual cannot sterilize through layers, and it dissipates when the boat is unused.

These bacteria, in the absence of oxygen, will use sulfate as an oxygen source (electron donor) and produce hydrogen sulfate and other objectionable smells, depending on the base water chemistry.

Additionally, if you put glycol in the tank in the winter (common mistake--glycol should only go in the lines) it will ferment and create bad tastes that are hard to remove.

---

Bottom line. If you visited a restaurant you would like to know that they clean and sanitize their water tank on a regular schedule, wouldn't you? You'd like to know that bugs could not crawl in the vent. You would probably turn down a glass of water that had been setting on the counter for several months. A good NSF 53 rated in-line filter, filling pre-filtration and annual cleaning, and you will be good.

[Lepke]

I like my RO water taste and run everything thru it. Dockside water often seems to fail the taste test. I still have to drain and clean the tanks. Bacteria that can live and grow in water tanks is in the air. When you use water from a tank, air enters to makes up the volume.
Unless you have a sealed tank with a daiphragm bacteria will eventually enter.
Brand name filters and systems are no better than many found on ebay, amazon, etc., but much more expensive.