Ask Mr. Smarty Plants

In terms of the quality of the water itself, those rivers are already watering surrounding vegetation and apparently is not polluted in any major way. I guess the biggest question we need to ask you is how did you intend to transfer the water from either river to your home in Hays County? One bucket at a time? I doubt anyone would object to that, but it would take a lot of buckets and a lot of car trips (with the accompanying air pollution) to get much to your garden. Were you planning to take a water tanker truck and load it up? I think the Guadalupe-Blanco River Authority might have a reason to object to that. The San Marcos River originates in the San Marcos Springs, which is fed by the Edwards Aquifer. You probably don't have a long enough hose to hook a pump up to either river and deliver the water to your garden, and I feel sure there would be objections to that.

The simple fact is that either your city water supply or perhaps a well on your property are delivering the same water, from the Edwards Aquifer to your garden faucet now. We know of no effects, good or bad, of using that water. It is alkaline because the surrounding soil is alkaline, and we can think of no reason to go to that much trouble, unless you just want to save on your water bill, but we have already pointed out that your local water district might have something to say on that subject. The best we can find out, the San Marcos water district is the Bexar Met Water District.