Exumas Mar ‘24 - drinking water from water maker

[Alaska Amber]

We have chartered several times throughout BVI’s and other destinations. Generally we can pick up bottled water along the way or we just boil water if needed. I have done research on the Exumas and we understand there are little to no places for provisioning once we leave Nassau. We are chartering a boat (Moorings) with a water maker and filter, but the idea of using tank water for drinking water and ice is not something I am not comfortable with. I plan to boil and refill jugs and ice trays. That being said, does anyone have any experience with charter boat water makers? Too risky to drink? We have 6 adults with healthy appetites for ice in their cocktails. I don’t want to be overly cautious and burden ourselves with boiling water constantly if that just overkill. Welcome any thoughts.

[Tin Tin]

You can buy a screw on filter that attaches to the galley faucet - they are not very expensive. You can then take it off and use on your own boat when you buy one, or your RV, holiday rental etc. Amazon has a bunch of them with different properties. Some have a multi-fit rubber connector. We have one from Britax. Other name brands like Pur and Cullinan too.

[Alaska Amber]

Great idea! Thank you. We have a boat here in AK, so that is perfect. Problem solved. Thanks again.

[GordMay]

If the R/O membrane is rejecting salt, it's likely rejecting most bacteria & virus pathogens, which are much larger than a dissolved salt molecule.

Ultrafiltration has a pore size of about 0.01 microns [μm], whereas nanofiltration filtres have much smaller ones, at about 0.001 microns.
The pore size of a SWRO membrane is about 0.0001 microns. [1/1,000μm]

Bacteria and viruses are much larger than a dissolved salt molecule, so only water molecules, and some mineral ions can pass through the RO membrane; and other impurities, and heavy metals, are discharged from the wastewater rejection.
For instance, the diameter of the coronavirus is between 0.08 μm ➛ 0.12 microns [ 80 ➛ 120 nanometers].

1 nanometer [nm] = 0.001 micron [µm]

Some pesticides, solvents, and volatile organic chemicals (VOCs) are not removed by RO.

Of course, after purification, bioaccumulation [contamination], can occur in the boat's water storage tank.


FWIW: "Da Spring" at Highborn Cay ➘

[SailingHarmonie]

Originally Posted by GordMay

If the R/O membrane is rejecting salt, it's likely rejecting most bacteria & virus pathogens, which are much larger than a dissolved salt molecule.

Ultrafiltration has a pore size of about 0.01 microns [μm], whereas nanofiltration filtres have much smaller ones, at about 0.001 microns.
The pore size of a SWRO membrane is about 0.0001 microns. [1/1,000μm]

Bacteria and viruses are much larger than a dissolved salt molecule, so only water molecules, and some mineral ions can pass through the RO membrane; and other impurities, and heavy metals, are discharged from the wastewater rejection.
For instance, the diameter of the coronavirus is between 0.08 μm ➛ 0.12 microns [ 80 ➛ 120 nanometers].

1 nanometer [nm] = 0.001 micron [µm]

Some pesticides, solvents, and volatile organic chemicals (VOCs) are not removed by RO.

Of course, after purification, bioaccumulation [contamination], can occur in the boat's water storage tank.


FWIW: "Da Spring" at Highborn Cay ➘

This theoretical calculation has no place in the real world and should be 100% ignored. It is correct, in a sense, but it only applies to a system that is 100% guaranteed to have ZERO bypass from high pressure to product water. Even a very small leak will contaminate the product water with pathogens at a level sufficient to make you ill if the feed water is contaminated.

On large commercial systems that are used industrially to make sterile water a bubble point leak test is performed every time the unit is started up. This is not possible on a typical marine unit.

If the feed water has a significant pathogen loading the only safe assumption is the product water does too. Clean, open ocean water does not have human pathogens in it, so is safe to drink through a typical watermaker. Water from a contaminated harbor, not so much.

[GordMay]

Originally Posted by SailingHarmonie

This theoretical calculation has no place in the real world and should be 100% ignored. It is correct, in a sense, but it only applies to a system that is 100% guaranteed to have ZERO bypass from high pressure to product water. Even a very small leak will contaminate the product water with pathogens at a level sufficient to make you ill if the feed water is contaminated...

... If the feed water has a significant pathogen loading the only safe assumption is the product water does too. Clean, open ocean water does not have human pathogens in it, so is safe to drink through a typical watermaker. Water from a contaminated harbor, not so much.

IMO: If a SWRO system is rejecting salt - then, it’s also rejecting pathogens, and safe to drink.
If the product water tastes salty, or measures a high level* of Total Dissolved Solids [TDS] it’s possibly un-safe to drink.

* The palatability of drinking water has been rated according to TDS level as follows: excellent, less than 300 mg/L [300 parts per million]; good, between 300 and 600 mg/L [300 - 600 ppm].
The USEPA Secondary Regulations advise a maximum contamination level [MCL] of 500mg/liter [500 ppm for TDS.

The method most commonly used for the analysis of TDS in water supplies is the measurement of specific conductivity with a conductivity probe that detects the presence of ions in water.
➥ https://www.amazon.ca/s?k=ec+meter&h...l_9gjpgr0w4r_e

For several reasons, it’s not wise to source [possibly] polluted water, for your SWRO system.

[Tin Tin]

Originally Posted by Alaska Amber

Great idea! Thank you. We have a boat here in AK, so that is perfect. Problem solved. Thanks again.

Just a tip. Boat hot water can be way hotter than home hot water, if there is a mixer tap make sure not to run super hot water through the filter by accident.

[Johan Leopard51]

The water from a decent water maker is perfectly safe for drinking, but it tastes crappy. We have an undercounter filter (Seagull I think) with a spout, tapped into cold water line that removes the taste.

It was becoming impossible to keep up with bottled water volume for long trips in space terms.

The icemaker on charter boat is likely plumbed into boat so that may be difficult to intercept.

One caution : an RO system likely strips out the good stuff along with the bad. I’ve noticed on long trips that I start cramping on extended snorkels. Likely the minerals are AWOL. So take some well-balanced electrolyte powders.

Instapure sells a carbon filter unit that can fit onto a faucet and runs respectable 3l per minute, but probably depends the size & shape faucet unless can fit some kind of rubber faucet and clamp it. It will be a PITA to have that on the galley tap and do the on-off for when doing dishes etc.

Remember US and Europe have different thread density, so plumbing connections from US might not work on all yachts.

[Leadfree]

Originally Posted by Alaska Amber

Welcome any thoughts.

I believe you have options, they have limitations.
--Highbourne Cay has small grocery like a convenience store and may have ice
--Norman's Cay marina may have offerings
--Warderick Wells has a small drinks stock in the park office
--Staniel Cay has plenty of everything
--Black Point is also fully stocked
--Little Farmers Cay may have offerings
South of LFC there is nothing until Great Exuma (Barraterre) but if you're chartering I expect that you won't have time to get that far.

You may contemplate the purchase of Addison Chan's very recently published cruising guide which likely has more detail.

[fxykty]

Originally Posted by Johan Leopard51

…

One caution : an RO system likely strips out the good stuff along with the bad. I’ve noticed on long trips that I start cramping on extended snorkels. Likely the minerals are AWOL. So take some well-balanced electrolyte powders.

…

Is this (lack of minerals in water) really a thing, other than possibly for taste? 95% of the water we drink comes from our watermaker, with some rainwater capture. We have not noticed any effects relative to when we lived on land and drank municipal water full of minerals. Doesn’t our diet provide all the minerals we need?

[Indolent58]

Originally Posted by fxykty

Doesn’t our diet provide all the minerals we need?

Yes it does, although with all topics related to health and nutrition opinions will vary.

[CarlF]

To go back to the original problem - how to have safe tank water on a one week charter.

1) R/O water made from any ocean water you’d be willing to swim in is safe to drink. The water already has very low bacteria counts and the R/O makes it much lower.

2) Faucet filters do just about nothing to make water safer - just better tasting.

3) The only practical way to make a charter boat tank safe is with a bit of bleach. In low concentrations (1 ppm is typical chlorine levels in municipal tap water. 3ppm is typical for pools). At 1ppm you can’t taste the chlorine or smell it but it will kill just about all dangerous bacteria. Take a set of pool test strips with you. Add 1/2 teaspoon of household bleach to 50 gallons of tank water. Wait an hour and measure. If it’s below 1ppm add another 1/2 teaspoon. If over, run some water out of the tank and make some new with the watermaker. Note this technique isn’t safe with extremely dirty water. You need to start with water that is believed to be potable and smells and looks OK. If it isn’t, have the charter base clean the tanks before you leave.

4) Take a Brita filter jug for drinking water. These do a good job removing any odd and chlorine taste from water that is already safe.

5) Recreational boat R/O systems do not remove all the minerals as a typical TDS is around 200 ppm - higher than some supermarket bottled water. Distilled water and commercial R/O water has very low TDS that can lead to mineral issues but even then it takes months - not a one week charter.

https://www.amazon.com/EASYTEST-Chem...1464607&sr=8-3

[Alaska Amber]

Thanks everyone. Appreciate the many replies. I’m going to implement a few measures! Great responses.

[NorthCoastJoe]

I think the place to look for problems is in the tanks, piping and faucets. All the pure water from the water maker is not clean as soon as its in the dirty pipes. If you are really worried about it get a backpacking filter/pump and run all the tap water through it to remove microbes. No boiling needed. I have had this model for over 15 years.

https://www.allfilters.com/campingfi...xW_t61falzewR4

[phorvati]

Originally Posted by Alaska Amber

We have chartered several times throughout BVI’s and other destinations. Generally we can pick up bottled water along the way or we just boil water if needed. I have done research on the Exumas and we understand there are little to no places for provisioning once we leave Nassau. We are chartering a boat (Moorings) with a water maker and filter, but the idea of using tank water for drinking water and ice is not something I am not comfortable with. I plan to boil and refill jugs and ice trays. That being said, does anyone have any experience with charter boat water makers? Too risky to drink? We have 6 adults with healthy appetites for ice in their cocktails. I don’t want to be overly cautious and burden ourselves with boiling water constantly if that just overkill. Welcome any thoughts.

I would not drink water from charter watermaker. Regardless of what fawcet filter you put. There is going to be bacteria in those lines and tanks after the desalinator. Storing and making healthy drinking water is not easy. desalinator is a heavy maintenance item and thinking that charter company is keeping it in good working order is way too optimistic. Provision your drinking water in nassau and use tank/desalinator maybe for tea and coffee and dishes/shower.