In San Juan, water has always had to be carried somewhere: down the canals that fed the Rio Grande Valley's citrus groves, along the rows, out to the roots before the sun climbs too high. Irrigation-Mart San Juan works in that same old current, keeping lawns watered and green in a corner of deep South Texas where a hard freeze comes only once in a long while and the heat hardly lets up. Palms rattle in the Gulf breeze along the expressway, the bell tower of the Basilica of Our Lady of San Juan del Valle catches the sunrise, and somewhere down the block a sprinkler head rises right on cue. The reward is simple and lovely to see: a yard that stays green and forgiving beneath a Valley sky in the middle of August.