Tech Wiki

Water Tank Commissioning

I hope to have the boat in the water soon and need some advice in commissioning the water tanks. I used the pink antifreeze in the water system for the winter. I would like to know what I should use to sanitize the tanks and what the process is. Should I use Clorox and if so, how much, how long should I leave it in and how many times should I flush the tanks?

Richard Beecham, Refuge #1430, Rock Hall, MD


  • We’ve had aluminum tanks on our Tanzer 29 for the last 13 years – now we’re looking at C34s. We use some pink antifreeze on “empty” tanks and flush through the pump etc. Probably it is best to try to drain a water heater. Anyway, we pump dry in the spring and then add a couple of gallons of water and pump dry – repeat until all the pink colour is gone. Don’t fill up the tank to get rid of the pink. Once the pink is gone then fill the tank after adding a couple of shot glasses of bleach per 25 gallons. Let pump through the full system and let sit for much of a day and then pump out and fill with clean water. During the season use lots of water when you know you can get more – keep the water moving and partway through the season add a shot glass of bleach. Murray Charlton

  • Go to www.planetcat.net and go to the page called “the head mistress”. There are some tips on head maintenance, water systems, etc at the beginning of the page. Everything you need to know, from an expert in the field. Rocco Palaia

  • For the past 12 years, except last year, I used Vodka in the water tanks over the winter. This seemed to work well in both Rock Hall, MD and Stonington, CT. Each year, however, I did blow out the water lines and empty the hot water heater. Last year, I used a small vacuum to blow out the lines and the tanks after disconnecting them at the water pump and the hot water heater. Seems to have worked just fine. In the spring I fill the tanks and add a little chlorine. As the water sits over the summer, it usually gets a little more chlorine as needed. I find that pumping the tanks dry repeatedly to sanitize them gets tedious although it is not exactly backbreaking labor. We usually buy a couple of gallons of Poland Spring for drinking and replenish these gallons from dockside water so we know that it is fresh and more or less algae free. One an earlier C34 (1989 model), I added a three gallon tank which sat abode the aft water tank. Fill and overflow hoses were in the stern locker. I ran it to the foot-operated sea water pump in the galley. We used that tank for drinking water since it was recycled pretty frequently, it was easy to keep clean. In the Chesapeake, I wasn’t going to use the sea water for much of anything, so it was, to me, a reasonable tradeoff. Phil Davies, Cat’s Paw #1360

  • I am becoming very concerned over the apparent waste of Vodka and its frivolous dispersion into the environment for the use under discussion. As a noted imbibing conservationist and environmental worry wort this practice is most disturbing. Furthermore, it could do irreparable harm to east-west relations if we in the west were found to be treating the national drink of the east in such a frivolous manner. It brings forth the vision of perestroika failing and the Berlin wall being reconstructed! Kissinger would have a Lady Bird. I have a better solution and a process during which I drink the vodka. I use RV antifreeze; while drinking vodka, I suck out all the water in the fall with a shop vac; pour in antifreeze and suck it through the system until the color shows; again, while drinking vodka, I suck the residual out in the spring with the shop vac; rinse and suck out twice with about 6 gallons of fresh water each time; fill the tanks; add a small amount of chlorine bleach (half cup to each tank) and away we go. For safe drinking water I have installed a high quality filter, (known to remove all potential bugs and taste) plumbed to a separate facet in the galley. The water is a fresh as a daisy and, more importantly, we are assured any stray tummy bugs etc. are filtered out. The filter is changed annually. More vodka is associated with this somber ceremony. As an added bonus I find I can save over half of the antifreeze to use again each year. Save all of the vodka, half of the antifreeze and contribute to east-west relations…. ain’t it great??? Gary Wiseman, Up Spirits #894

  • BLUE MOON’s water supply is rarely frozen in Southern California and therefore hasn’t the same requirements as those boats East of Las Vegas. However, having learned painfully my lesson about not heeding this list’s advice I have faithfully replaced BLUE MOON’s water supply with vodka. <hiccup> signed, mud. John LeMasters, BLUE MOON #753