Sorry if I'm slow with my thoughts, but I'm going to assume that a law allowing wastewater to be reused is not really about finding a reuse of the water or frankly even disposing of it. If O&G can "safely" reuse wastewater for agriculture, then why not allow them more access to more groundwater. They'll return x% of it back to the river or agriculture canals at a later date. Let's face it, O&G wants 100% of Texas water so they need to identify how to sell that argument.
In a way, it reminds me how the chemical industry came up with the idea of plastic recycling. Not because they wanted to reduce landfill waste or that they wanted to buy recycled plastic. They wanted to shift the blame of plastic waste in our environment away from them. Chemical companies aren't the bad guy, it's your neighbor who refuses to separate their trash. This gives the chemical companies more of a market because the consumer doesn't feel bad about choosing plastic.