As the water was getting colder back in November, I started noticing that the sleeves of my drytop were starting to get a bit damp, to the point where it was getting somewhat uncomfortable to continue playing for long periods of time. It's a known fact that the DWR (durable water repellency) wears off after a while, and my drytop is now about 4 years old so I figured that could be it.
After looking into the cost of getting a new drytop, I decided to try revitalizing what I already had to see if I could extend its life. After all I had just spent $40 already on a new neck gasket, so I figured I might as well get some use out of it.
I did a little research on google and found that everyone seemed to be recommending the Nikwax Tx-Direct wash-in waterproofing treatment. The drytop is Gore-Tex, and the Nikwax treatment is designed to work with all breathable fabrics of this type. For non-breathable drytops perhaps a spray-on treatment should also be considered.
I went over to REI and picked up a bottle of the Tx-Direct as well as the Nikwax Tech Wash, total cost under $20. The treatment consists of washing the drytop first in the washing machine with the Tech Wash, then washing it again with the Tx-Direct. You need to let the Tx-Direct soak into the fabric for some number of minutes after the washer has filled, otherwise you just set the heavy wash cycle and let it run. The only other thing to keep in mind is that you can't put the drytop in the dryer if it has latex gaskets, so I did a combination of warm-iron and blow-dryer to activate the DWR.
I was skeptical at first, but I am happy to say that the waterproofing treatment worked like a charm and I was able to stay quite dry in 40-degree water. So if you're considering getting a new drytop, you can save some money by trying the Nikwax treatment first.