We have camped at Port Aransas, which is quite a long way from Brownsville, but didn't find the water objectionable. However, we, like you have a filter, etc. We do carry a case of bottled water that we use if going on day trips. The only water problem I remember was in Las Cruces, NM where DH had to chip the calcium build-up off the water faucet before he could hook it up. Thank goodness we were only passing through and spending one night there.
