Watermaker Reverse Osmosis (RO) Membrane Change:

One of the most important on-board systems is our water maker. It’s been “pickled” for nearly 3 years – meaning its been in preservation mode since we were not using it. It was time to clean it and replace the reverse osmosis membranes… now that we are cruising.

As part of our cruising maintenance routine, we inspect and clean our water maker gear. We have a 60 gph unit aboard SV Take Me There with two RO elements. I ran the appropriate start up procedures and tested the RO output water with a coliform test kit and got a “positive” (for coliform) result. We were getting good Total Devolved Solids (TDS) reading from our test meter (about 78 ppm) but we had coliform. We de-scaled (cleaned and flushed) the system by circulating a low PH solution and ran another test – which was also positive. So – we had to replace the RO membranes at nearly $200 per element.

We ordered them and had them shipped into our last stop – today was “replacement day.” 4 hours later, the system is clean and ready for a new sample run – which we will not do until we are underway since “harbor water” at the marina we are currently sitting in can contain petroleum products (bad for RO membranes).

We test our “product water” regularly using coliform test kits we order from Amazon and we keep at least three test kits on hand at all times. NEVER divert product water to your tanks until your coliform test is negative! It takes 48 hours to see test results!  It had been a long time since I performed these procedures so I studied the manuals and gladly remembered three key process rules:

1. Never use water that has been chlorinated to flush or test your system – it will ruin the RO membranes.
2. Be sure to check the oil in your high pressure pump and change it every 50 hours of operating time to keep the pump happy.
3. Keep your pre-filters clean – especially if the source water is silty (like in the Chesapeake).

Our water maker is a work horse and we depend upon it heavily as we don’t like the alternative of hauling water to the boat in the RIB – nor do we like paying for water at stop-overs…not such an issue in the US but in other remote areas you may pay by the gallon!

Our message in this post is – if you have a water maker…take good care of it and it will serve you well!

We are finishing up our marina visit in Oriental, NC and will be moving on to parts South soon. We will wrap up our stay in this quaint “cruisers” town with a trip to the local marine consignment store, a hardware store and a quick shop for some “nice to have” groceries.