UV Water Sterilization

[Wbarnh]

We are purchasing a 1995 Ocean Alexander and the pre purchase surveyor has included installing a UV Water Sterilization system.

We had a 1977 Grand Banks 36 before and the only thing we did was add a sediment filter.

I've read the posts available for the last couple of years and our surveyor's recommendation seems like overkill.

Opinions? Does anyone use UV sterilization on their trawler?
Thanks
Barney

 

[Comodave]

On a previous boat we had one. It had both a sediment and UV element. We drank the water out of the tank and made ice out of it too. Our current boat doesn’t have one so we don’t drink the water out of the tank. Lots of people do drink out odf the tank without any filtration, but we prefer not to.

 

[Lepke]

I make all my water with RO and use a UV light as the last process before the water goes in the tank. I don't use dock water.

If the light is after the tank, there's a few problems. The light tube has a limited life in hours before it becomes ineffective. The light takes a few minutes to warm up and become effective. So unless you leave the light on and replace the bulbs often, probably monthly, they don't do much good. It's easier to keep the tanks clean and use the light to sterilize incoming water.

 

[lipets]

I'm in the water filtration business, to filter the water before the tank is not the most effective use of any system.

Out of the tank into at least a two stage filter sediment/carbon works very nicely to give you drinkable water.

to upgrade from there a add a UV (perhaps) but a Reverse Osmosis with a separate tap for drinking.

A UV is generally turned on 24/7 in a home but on a boat or RV is when you're aboard.

the bulbs last 9000 hours or one year in a home.

Personally I have a UV in my home not on my boat.

I have the two stage and reverse osmosis.

 

[mvmahal]

We have after tank sediment filter -> carbon filter -> ceramic filter - UV picked up the uv off ebay for around $40 and then found a 12v supply for it on amazon for around $30 the ceramic and uv are on there own tap for drinking water and ice. we put a simple toggle switch to off the UV, I have just picked up a faucet with a switch in it as well which I plan to install instead to automatically on/off the UV.

I have used similar setup on last 2 boats and in our house before and happy with it.

 

[lipets]

how many watts is a $40 UV?

 

[mvmahal]

the one I have is 25w

 

[lipets]

Interesting a 25W bulb cost more than $40, most 25w UV's are about $150-200+

 

[mvmahal]

I believe the prices were around 130ish like that when I was looking. The seller posted a few the same for like 40 / 60 / 80 etc.. I was only bid and got it. so just keep your eyes / tracker what ever on eBay and one may show up for you. Unfortunately my search right now only shows one for $139 so a bit more.. Actually just check I paid $39.90 for it 4yrs ago Seller was fullyfish2016

Good luck in your search..

 

[Comodave]

We used to leave the UV on 24/7 and changed the bulb each year.

 

[twistedtree]

We focus on keeping the tank and plumbing system sterile in the first place, and drink directly from it. Consumed water only goes through a carbon filter to improve taste.



To keep it sterile, we do different things depending on where the water is coming from:


1) Treated dock water: Dock water from any developed area is treated, and we put it straight in the tank. The treated water helps treat the tanks and plumbing system, so improves the sterility level of the water system.



2) Watermaker output: This is already sterile, so goes directly into the tank. This is neutral to teh sterility of the system, neither helping nor hurting.



3) Untreated dock water: This we assume is bad, and treat it on the way to the tank. It gets filtered for sediment etc., then runs through a UV sterilizer. The goal here is to not introduce impurities.



Periodically, especially if we have run a long time without any treated dock water, we will treat the tank with a shot of bleach.

 

[Alaskan Sea-Duction]

I have 2 filters after the tanks and before the pump. In our travels we have always filled our tanks with city water.

We also have a water maker.

Is a UV light really necessary? I don't cruise the Caribbean or Mexico.

 

[FF]

"Fuel polishing " is usually a waste of effort as it only cleans the fuel, not the tank.

BUT this is just what is needed with potable water.

With a few min. to let the lamp warm & function it might be easy enough to "polish" suspected water while underway , where the electric demand can easily be met.

This might require a better quality water pump if its going to be on for hours.

 

[sailormike]

On all the cargo ships I sailed on we had uv filtration after the pumps. on one ship we had clorine injection too.



On our boat we always drank tank water and at least once a year we would sterilize the system with bleach.


During my last replumb I added a UV filter after the water pump to only treat the tank water.



I also added one as the last stage of our watermaker before it goes into the watertank.