How to keep water out of the brake lights?

[svxsubaru1]

When i first bought my SVX around 1 year ago the rear barke ligts never had water in them, now they had alot of water in them really took away from the apperance in the rear, so to day (first day of summer break) i took them off and got all the water out of them by using a hair dryer. I really dont want to spend a couple hopurs every month to get the water out and i was wondering what to people do to keep it out? I called up a dealer and they said they dident carry the gasket for it, and i cant seem to find one on subaruparts.com.

Thanks