The Lawn & Garden Water Smart Tax Holiday was created in 2016 to encourage responsible water use in Texas. Over Memorial Day Weekend, retailers can sell select water saving products without charging sales tax. Below is a list of the items that qualify for the sales tax exemption:

WaterSense Products
During Memorial Day Weekend, retailers do not need to charge sales tax on any product tax free that displays a WaterSense label or logo. These items can be bought for either personal or business purposes.
Water-Conserving Products
Consumers can also purchase certain water-conserving products tax free. Unlike WaterSense-labeled items, these items are only exempt when purchased for use at a residential property.

Items are tax free during the holiday that are used or planted for:

conserving or retaining groundwater;
recharging water tables; or
decreasing ambient air temperature, and so limiting water evaporation

Examples of items that qualify for the exemption include:

a soaker or drip-irrigation hose
a moisture control for a sprinkler or irrigation system
mulch
a rain barrel or an alternative rain and moisture collection system
a permeable ground cover surface that allows water to reach underground basins, aquifers or water collection points
all plants, trees and grasses
water-saving surfactants
soil and compost

Examples of items that do not qualify for the exemption include:

construction/building materials
awnings and other items used to create shade
air conditioners
ceiling fans
sprinklers