Short Answer: Make your own water maker. It’s cheaper, it makes more water, and you’ll know how to fix it without a high-priced mechanic.
Long Story: DrC just finished making our water maker. We downloaded the plan off the Internet a few years ago. I understand you can now pay to download this plan. I recommend it highly. We’ve met three boats to date who successfully followed the instructions to build and maintain a high-volume water maker. Now we are the fourth who can make the case for a home built job.
In the interest of fair disclosure, building your own water maker is not for the faint of heart. It took a long time and a lot of hard work. It is also not exactly cheap. The parts for our water maker totaled just under two boat bucks. DrC estimates it took him roughly 50 hours of work effort from start to finish not including what felt like 100s of trips to the hardware store. He does recommend that you build your water maker before you leave the dock. The critical tool is apparently a car to get to a really good hardware store. The most expensive parts are the filter, the pressure vessel, and the pump. The pressure regulator and clutch can also run you some change. You’ll also need space for the installation (~1.5 cubic feet), a thru hull or T off an existing raw water intake, and hydraulic hose to get the water to your tank.
There are two major advantages to building your own water maker: price to output ratio and maintenance. Even two thousand dollars is cheap for a water maker that puts out thirty gallons an hour. A comparable volume Spectra will run you at least $4,000. For roughly another ~$400 we could double our output to 60 gal/hour with a second filter. We’re considering it, but we’re going to wait until we live with what we have for awhile. Also, we hear folks on the cruiser nets almost daily asking about how to get maintenance for their water makers. There is something of a black box feeling for these devices down here. However, all the boats with hand built jobs tell stories about how a trip to the hardware store solved this problem or that. When you build it yourself you know how to fix it; It’s that simple.
Yesterday, we stood on the deck passing around a glass of clear, clean water. The entire family was grinning like loons. The water tasted like ambrosia after all the effort DrC had put in. So maybe a third advantage of DIY water makers is the sweet taste of accomplishment.