Treated pickets last longer while exposed to the elements, but there is some downside to this option of the fence. Because of our beloved Texas weather, (snowing one day and 105 degrees the next) elements cause many of the treated pickets to warp and cup. While the fence turns out straight at first, 6 months later, you have a less appealing fence to look at. We do offer treated lumber fences but recommend using steel fences poles instead of treated 4 x 4’s for durability and strength.