The performance of your spa will not be affected by a slight slope in your spa pad or it’s structure. There should, however, be no dips, sags or unevenness in the pad. Generally, most patios are built to slope away from the house in order to allow for drainage. Keep in mind, however, that there should be no more than a ½” (1.27cm) slope in an 8‘ (2.44m) run. Do not use shims to level the spa as this may damage your hot tub.