I have three questions, but for them to make any sense, I should explain what I have in mind for my boat. I am thinking of pitching my 50-gallon freshwater tank and replacing it with some filters and a uv chamber. I hope to get some advice from those of you who have some experience purifying lake water.

Here is what I have come up with so far:

Step one:
As a first step, I was thinking of using something like a Shurflo Extreme-series Strainer to remove any big junk before it gets to my water pump.

Step two:
After the strainer, I need a pump. My existing pump from my soon-to-be-trashed freshwater tank is a Shurflo demand pump. If memory serves, it is either a 3.5 or 4.5 gpm with a shut off at 45 psi. I was thinking of reusing it for my new system.

Step three:
After the pump, I think I need a sediment filter. You can buy a Shurflo brand like
this one for over $50, but they struck me as a little pricey and look just like the ones you buy for a lot less like this from a water-purification company.

To go inside the sediment filter housing, I was thinking of filtering down to something like 5 micons. I had something like this in mind. They are pleated filters and they are cheap to throw away when they fill with junk. I might just put one with each trip to the houseboat.

Step four:
I was thinking of using another filter housing, just like the one for the sediment filter. But this one would get 0.5-miocron-carbon filter like this one. The half-micron size takes out giardia and cryptosporidium. The only thing remaining at this point would be bacteria and viruses that are small enough to get through the carbon filter.


Step five:
You could probably drink water that had gone through a half-micron carbon filter, but to be on the safe side, it would be nice to zap any remaining bacteria or viruses. To kill them, I was thinking of a uv light that runs on 12 volts. The Water Fixer Company makes a good one for about $300. I would have considered one that is all put together for $450, but I barely have room for the 10" filters and the way they mount the chamber on top of filters uses too much room.

After going through a strainer, a sediment filter, a carbon filter, and a uv chamber, I am thinking that lake water should be tasty and clean. Total cost of the system should be around $400. It will require some maintenance, but that should take less time than going to the dock to fill my freshwater tank. And I like having a freshwater tank size of unlimited.

After that long windup, I have some questions for those of you who know something about this. First, I am supplying three "candy cane" taps and want to have future capacity to expand for an icemaker and fridge with a water dispenser. A seat-of-the-pants estimate tells me that this puts me in the four gpm range. That's okay, but the four gpm uv chamber uses 25 watts at 12 volts. Not a big draw, but my boat still has a single 12v house battery and I don't plan a battery bank and inverters for a few years. For that reason, a smaller uv light chamber that uses 10 watts and sterilizes 1.5 gallons per minute sounds tempting.

My second question has to do with the sediment filter. A standard filter is about 2.5" in diameter. There is also a "big blue" diameter that is about twice that diameter and will hold about twice as much junk before it fills. But the housing and filter also cost about twice as much. If I can get by with the standard diameter 10" long filter, I like having just one filter wrench and the lower-cost filters that I can replace more often.

My third and final question is this: Is this all just plain crazy? I have never been on a boat with a filtration system and I am just guessing that this will all work. Will this system work as I am describing it?

You're overlooking one very important step: purification. Federal water quality standards for swimming waters allow a bacteria count of up to 200/100 ml, which is well above the allowable amount for potable water.

You wouldn't be able to do without a water tank, because it's only advisable to take on lake water when you're in deep water well away from shore. The contaminants in marina water would destroy the system...nor would you want to take on lake water when you're beached in shallow water where sand and dirt are being stirred up by activities in the water...not to mention some pollution from runoff. So unless you're careful in how you use it, you could end up creating a dozen new maintenance problems instead of solving one.

So I suggest you do some research on fresh water watermakers...typically reverse  osmosis systems, but also filtration and treatment systems too. There are also companies who specialize in the types of watermakers you're looking for...and if you decide to do this, I recommend you go with one instead of attempting to cobble up something on your own.

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Peggie Hall, Moderator
Specializing in marine sanitation since 1987, Author: "Get Rid of Boat Odors--A Guide to Marine Sanitation Systems and Other Sources of Aggravation and Odor."
[L=http://shop.sailboatowners.com/books/detail-books.htm?sku=66438&cat=1304[/L]

Peg, many thanks for taking a look at my scheme. Purification was the fifth step in my admittedly long explanation., so I can see how you might have missed reading that part. I understand that a UV light chamber, properly used, is effective as a complete kill for bacteria and viruses.

As for marina polution, my boat is on a buoy well away from gas pumps and the like. Typically I use the boat beached. I am at Lake Powell, so polluted water running onto the beach is not an issue. My existing water pick-up is just behind mid-ship. My existing pick-up is for bathing and has stayed pretty free of silt and sand. I am thinking that a parallel pickup a few inches away for purified water would likewise stay reasonably clear of sand and silt.

I considered reverse osmosis, but you can get a membrane tear and not know it. That struck me as a possible problem. Any good RO unit would require a sediment filter as a pre-filter and would have a carbon filter for taste, so the RO part seemed unnecesary and added complication and cost for little if any benefit. Besides, if my boat sits unused for a few weeks, I worry about water stagnating in an RO unit. With filters, at least I can unscrew the filter canisters before I leave and set them on the kitchen counter to dry.

I would have liked to go with an already-assembled unit, but don't have room. My existing pump and plumbing is under a bunk and to change the location would take a fair amount of cabinet and plumbing work. It takes about 14" to leave enough room to mount and change a 10" filter, so I don't have space for the typical pre-assembled units that stack the UV light chamber or RO unit on top of the sediment and carbon filters. Besides, attaching 1/2" FPT (female pipe thread) devices to each other with tubing or pipe nipples and using screws to attach devices to existing plywood isn't exactly rocket science.

So with those explanations, is this still a harebrained idea?

I'm not an expert in it but I'd still keep the fresh water tank, even if you fill it with purified lake water. At least that way you can pick and choose when/where you get your water. You'll need an extra pump, but if the purification system goes down or doesn't work out, you'll still have the "regular" system.

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Willie
She's a tired old barge but she's paid for! http://s71.photobucket.com/alb...p;current=ef324993.pbw

Edited: 02/04/2009 at 01:17:53 PM by stmbtwle

You said, "I understand that a UV light chamber, properly used, is effective as a complete kill for bacteria and viruses." Do you have the knowledge and expertise to know what the proper use is to ensure that your water will be potable quality/"

And Where'd you get the idea that all systems offered by companies who specialize in water purification systems are "preassembled?" Their literature may include illustrations of completed systems, but most if not all are custom fitted to the boat. I strongly recommend that you talk to some of 'em.  

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Peggie Hall, Moderator
Specializing in marine sanitation since 1987, Author: "Get Rid of Boat Odors--A Guide to Marine Sanitation Systems and Other Sources of Aggravation and Odor."
[L=http://shop.sailboatowners.com/books/detail-books.htm?sku=66438&cat=1304[/L]

I have built my very own water maker system very similiar to what you are describing. First I used a 110v well water pump to pump water through a strainer from the lake. Then the water went through a pool chlorinator and to a swimming pool sand filter. I filled the sand filter with a pebble media and sand in layers to take all the big stuff out of the water and it allows me to backwash the system when I am hooked to the dock. I then pump the water to two 5"x10" filters, one is a sediment filter at 10 microns and the other is a carbon filter at 5 microns. The carbon filter also removes the chlorine from the water. Then I pump to a .5 micron filter in the waterfixer and finally to the uv chamber then to the faucets. I do not recommend hooking this configuration to any ice-makers. Also I keep a water test kit on board to monitor bacteria, viruses, chlorine and other contaniments. Peghall is right, do not use this configuration in shallow water and/or in the marina. I still have my fresh water tanks i use when located at the dock but when I am out on the lake where the water is fairly deep and clean I purify my own water. I realize some people may disagree with the concept but I have been doing this for 3 years and no problems to date. Good luck

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Sincerely,
Jason

Miss Sandi

Peg, you asked about my expertise in using a UV chamber. On the scale from expert to clueless, I count myself as closer to clueless at this point. For that reason, I came here to get some knowledge. That's why I am so grateful for input from people like you, stmbtwle, and Jason.

To properly use a UV chamber, here are the Dos and Don'ts that I have learned so far:

1. Do pre-filter water. To work on bacteria and viruses, the UV light has to shine on them. If there are big enough particulates in water going through the chamber, a bacterium or a virus could be shaded by a 20 or 30 micron "rock" as it floats through the chamber. If you fliter the water before it gets to the UV chamber, you remove that risk.

2. Do buy the right size unit. For the UV chamber to do its job, water has to stay in it long enough. So if you buy a 1 gpm unit and pull water at 2 gpm, the water stays in half as long. The right way to size the unit is to add up the flow rates of all of your water taps so that if someone turns them all on at once, you still have purified water.

3. Do replace the lamp at regular intervals. A typical UV lamp is good for 9,000 hours. After that, they still make light, but at an intensity that can't assure complete purification. 9,000 hours is about one year of 24/7 use, so weekend use in a houseboat could be many years. Still, a new lamp only costs about $25, so I would rather just replace it every year or two in case repeated starts and stops shorten the lamp's life.

4. Don't leave water in the unit in freezing weather. The chambers are mostly stainless steel, so they will burst if they freeze when they're full of water. I winterize my houseboat anyway, but I am shopping for a unit with a drain petcock to make winterization easier.

5. Do give the lamp time to start. The UV lamps take a half a second of so to warm up to full effectiveness. So you either need to turn the lamp on first with a separate switch or use a single switch and a delay relay to cause the pump to wait a second or two after the lamp starts.

From responses here, I can add two more items to my list:

From stmbtwle: Do keep a traditional system as a backup.
From Jason: Do have a way to test the effectiveness of your system from time to time.

As for hiring someone to design and install a system, I haven't found anyone closer than 1,000 miles away that does these. As nearly as I can tell, professionals who do this tend to be in coastal areas like Oregon and Florida and houseboat capitals like Kentucky and Tennessee. These guys are happy to sell either complete assembled units or components. Either way, they have already given me what I consider as excellent advice. But to hire them to install a system would be costly or impossible. They would lose the better part of a day each way flying to and from my airport. It takes the better part of a day each way to drive from my airport to and from the lake. I'm guessing they would allow a day to install the system because they are hauling tools to a remote location and driving a two-hour round trip to the nearest parts store. That pretty much takes their work week. Besides, if the system needs work when I am 50 miles from the marina and 1,000 miles from the installer, I would enjoy the knowledge that came from designing and installing my system.

In the arid west, I guess we still have to practice a little more self-suficiency than in other parts of the country. But to do that, I hope to get more advice from those who traveled this route before.

My first reaction is, "Do you want to be drinking some of the nasty stuff I've seen go into the lake?"

I guess lifestyle is a big consideration. My houseboat is also on a buoy. We have a 30 gallon water tank. We don't drink that water, we only drink bottled water or other beverages we carry on each outting. We don't live on the boat but we do spend many long weekends aboard. Last summer I think I only refilled the tank twice. I did carry on a 5 gallon jug a few times when we didn't have much gear to carry on just to top off the tank.

My wife and daughters know not to leave the water run-- you wet your hands, soap them, then a quick rinse. Dirty dishes are first washed off in a bucket of lake water, then soaped with a sponge and a quick rinse in the kitchen sink. If you want a shower, it's a 5 second wetdown, soap up, shampoo if you want, then a 10 second rinse.

Probably the biggest water saver is the fact that we have an Electra Magic recirculating toilet. I know a lot of people don't think highly of recirculating toilets, but I charge it with 3 gallons of lake water (no fresh water is used) and our family of 4 can use it for two days. No odor complaints ever and believe me my wife is particular. I only have to pump out our 25 gallon holding tank about once every 5 or 6 weeks.

Labor Day weekend we stayed on the boat Saturday thru Monday and had 12 guests aboard for a party. I monitored water usage that weekend and we only used 6 gallons total.

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Mark
1979 Crest
Brookville Lake, IN

My main question is: Why do you want/need to get rid of the tank?

If I understand correctly this will be just for drinking water, your bath water (how about dish washing?) will come directly from the lake. For just drinking purposes it wouldn't require a very large tank to supply all the needs for a week.

If the issue is just the hassle of getting the boat over to the dock where you can get fresh water then I would recommend keeping the tank and use your filter system to fill the tank rather than supply water on demand.

There are a couple of concerns that I have about your suggested setup:

1) There will be a major pressure and flow drop going through your filter system. I suspect that you will need an accumulator tank after all the filters and possibly a second pump.

2) I would be very concerned about the "on demand" capability of the UV system. In can take a considerable amount of time from when you first apply power until the lamp settles down and starts emitting the proper UV light. If you rigged it up such that the lamp turned on with the pump there could be a significant amount of water passed through without getting proper UV exposure.

3) The single 12v battery: I am surprised that you can manage on that to start with, let alone adding another significant draw.


Here is my idea of how I would approach this problem:

A) Install a solar panel on the roof. Lots of benefits from this beyond fresh water. I would go for a 50 watt panel, but even a 25 watt would be enough.

B) Buy a standard household RO unit (which would come with an accumulator tank), an extra "spin on" filter installed ahead of the RO, the low capacity UV unit installed after the RO unit, and another pump and small accumulator to supply water to the system. You will also need a 12 volt solenoid valve.

C) the hard part, unless you are into electronics, will be to come up with the necessary timer to make this all work.

Here is the idea: The water pump and RO unit is operating 24/7. I would expect the pump to cycle on every 10 minutes or so to keep pressure up to the RO system, but it would only run for a few seconds.

Every few hours you turn the UV system on, give it time to stabilize, then allow the water to flow from the RO accumulator's tank through the UV unit and into the large fresh water tank you already have. Every few hours you will get a couple more gallons of water. You want the flow to be small so restrict it down. You might want to reroute the RO plumbing a bit to put the Carbon filter after the UV system. I would expect that the lamp would be on about 10 minutes per cycle.

I would expect the entire system to require around 5 amp-hours of power per day. A 25 watt panel would provide that with as little as 4 hours of sunlight per day. I would expect it to produce 15 to 20 gallons a day, which you store in your existing tank. The system in in continuous use so water doesn't get stagnant sitting in the system for weeks at a time.

Rod

I would have a very hard time drinking water that came from a lake. Then again, I wont even drink city water at my apartment nor will I drink the dock water at the lake. All the water that comes into our boat is ran through a carbon filter which is changed once per year(not used in winter). Not sure what micron the filter is since it was on the boat with refills when we got the boat. I would like to get a new case and a bigger filter so we could filter more water. Thought about getting a set from here:

http://www.pwgazette.com/gardenhosefilters.htm


What size fresh water tanks do most people have that worry about water usage? Weve got two 71 gallons tanks and weve never had any water problems. Longest weve stayed on the lake was 3 nights. 3 of us took normal showers nightly with normal water usage during the days. Brushing teeth, washing hands, doing dishes in the sink, etc. I believe we ended up using around half of our supply or ~70 gallons according to the tank gauge.

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1990 16x78' stardust
Eastern Ky

Edited: 02/06/2009 at 08:04:54 PM by Jeepster04

It's not that hard; just turn the water heater off and tell everyone it's "broken".

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Willie
She's a tired old barge but she's paid for! http://s71.photobucket.com/alb...p;current=ef324993.pbw

What's this? Other houseboaters can take hot showers on their boat?
I removed the water heater from our boat. It took too much generator time and gas to make a little warm water. We are on a buoy with no shore power.

If it's too cold to take a cold shower, you shouldn't need a shower. Cold water cleans dishes as good as hot.

Once again, it's all a lifestyle thing.

Growing up our house had a cistern filled by rainwater from our roof. When it didn't rain for long periods it was very costly to have water hauled in. We were allowed 2 minutes to shower--- period. And then my Dad would flip off the water pump switch.

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Mark
1979 Crest
Brookville Lake, IN

"What size fresh water tanks do most people have that worry about water usage? Weve got two 71 gallons tanks and weve never had any water problems. Longest weve stayed on the lake was 3 nights. 3 of us took normal showers nightly with normal water usage during the days. Brushing teeth, washing hands, doing dishes in the sink, etc. I believe we ended up using around half of our supply or ~70 gallons according to the tank gauge. "


I can't believe 3 people would go through 70 gallons in 3 days! As I said in my eariler post, Labor Day weekend we stayed on the boat 3 days and had 12 aboard for a party and only used 6 gallons.
With restricting shower heads, a quick shower should not use more than a gallon or two.
Are your toilets using fresh water or drawing lake water?

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Mark
1979 Crest
Brookville Lake, IN

Heads use lake water.

I would say we used 6 gallons of water just washing dishes.

Not 100% sure but I think our shower head is around 2GPM. If we take 5 minute showers thats easily 90gallons for 3 people over 3 nights. Given we turn the water off while washing, etc, 70gallons is about right.

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1990 16x78' stardust
Eastern Ky

Just a note,

I have a Kentwood Water Cooler with purified water on my boat for drinking. I use the water maker for bath water, toilet water, dish washer, and clothes washer. It does take a little common sense to know when and where to use lake water. I will not use it at the marina or if there is another houseboat dock close to us. I would forget the timer idea and just turn the light on and leave it on for the duration you are spending at the houseboat. It takes more electricity to start this lamp than it does to just keep it on. Again these are just my thoughts, Good Luck!

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Sincerely,
Jason

Miss Sandi

                           I have been on a 60x20 shantyboat for years on the Ohio river and tributaries. One single guy & two kats, FUZZY & TIMBERHEAD.  I have three 300 gal tanks for non potable water. This could be scaled down for a smaller boat. I filter raw river water in 300 gallon batches, then transfer it to the next tank to use out of.           House type 240vac water heater & pump, generator or shore power.

                 Use a diatomaceous earth type swimming pool filter with an ordinary swimming pool pump of  the correct size for the filter.  A sand type pool filter will not work as well for this job because it is not fine enough to take out silt & algae particles which are 1 micron or less in size.  A small hardware store cartridge filter won't get all the particles out on a one time through basis even if it is rated at 1 micron because  that is not an absolute rating. You need recirculation. if you want it really clean.  This setup will work even on very muddy spring run off creek water.  Pump and filter must be set up to recirculate water in the tank, just like a pool.  It will take all the color out of the water  in 45 minutes. It will be sparkling clear but still germy.  Once the water is clear I add about 10ppm chlorine & let run long enough to mix well.  After the chlorine kills the germs I usually end up with about 2-5ppm residual. You can verify this with a pool test kit.  This water is fine for showers, laundry, dishes, etc.  If you're worried about it, use more chlorine. This is about all many municipal water works do- just filter and chlorinate. I run hundreds of gallons before I need to backwash the DE filter.

                             For potable water, pour this filtered & chlorinated  water into a Berkey purifier. It requires no electric power or water pressure, only gravity. No UV lights, multiple elements, additional pressure pumps, or fragile expensive membranes. This purifier is used by missionaries worldwide.  It  will handle really bad water if necessary. A Berkey will purify raw river water in one step but by using the clear water I only have to clean the elements once or twice a year. You scrub these under clean running water with a piece of scotchbrite. Takes about 5-10 minutes.  If you use the black Berkey elements they will remove the chlorine. You can easily make your own Berkey type purifier if you don't want to pay for a real one. Get a construction type water cooler with a spigot. This will serve as the reservoir (lower chamber). Buy a set of Black Berkey replacement filter elements. Install these elements through the bottom of a new plastic bucket & set this on top of the water cooler.  You could use two stainless stock pots or any kind of container.

Shantyboat Mike,
Rabbit Hash,  Ky.

Edited: 03/01/2009 at 03:17:52 PM by shantyboat

Hey, Mike, I never heard of Berkely filters. How/where did you find your Berkley stuff? Phone number? e-mail address? Give your Kats a head rub for me/ Paul

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lookin' for adventure and the next wild engine!

Paul,
               So sorry for the belated reply. Have not been monitoring this forum.

Read my post again. It's BERKEY not Berkley. Just Google Berkey or Berkey filter. There are many sources to buy one. All you really need are the filter elements themselves. Get the black Berkey elements. They have activated carbon.
The unit I have is clear Lexan so you can see how much water it takes to fill without overflowing.

Mike

We use the Water Fixer 1000 on our Lake Powell houseboat.  We have a 20 gallon water tank that provides for the entire boat (shower and sinks).  We use the Water Fixer to fill the water tank.  This way we do not need to leave the UV light on continually.  We have a RV pump that has tubing that goes through the floor with a screen on it for the big chunks.  This pumps water to the Water Fixer which is connected to a water hose.  When we start the pump and Water Fixer we just let water return to the lake for a minute or two.  Then fill the tank.  The tank is small because I don't like to let non chlorinated water stay in the tank.  We fill about daily.  The water tank is setup like most with its own pump.  Water tests have shown the water to be potable but the levels of selenium are somewhat elevated.  Drinking this water for a month or 2 a year should be OK.  I am new to this forum and we have a small houseboat at Lake Powell that we recently remodeled.  I hope that I have been able to add something to your posts.  

Welcome Randy and many thanks for the local input. After receiving some excellent input here, I have decided that it will be better to keep my existing water tank and then re-fill it using a slower system as you are describing. I am happy to hear that it works well for you. Truth be told, filtered water from the lake that is treated with a UV system is probably better than what comes out of the tap at my home. I don't think I'd do it at a lake that had problems with heavy metals or other pollutants, but I am confident it should be fine for Lake Powell.