Texas is a big state with a range of natural environments. While property owners in the state's well-watered eastern section rarely clash over issues relating to the capture of groundwater and surface water, water rights are a frequent topic of conversation in Texas's western two-thirds. Landowners and business owners who need more water than the average consumer must understand the "Rule of Capture" and other groundwater-related issues. 
Defining "Groundwater" and "Surface Water"
Under Texas law, "groundwater" is defined as all water that percolates beneath and through subterranean rocks and soils. To drive this point home, it's occasionally described as "percolating water." By contrast, "surface water" is any water that pools or flows in plain sight. Subterranean rivers and streams comprise a murky area of the law: It's unclear whether subterranean sources of flowing water can be considered groundwater, and Texas law assumes that all non-visible sources of water are "percolating."
What is the Absolute Ownership Rule?
Texan landowners are said to be "absolute owners" of the groundwater underneath their surface parcels. They have the right to pump and use this water at will. Unlike minerals, however, landowners can't profit from the use of their groundwater without specific permissions. Under normal circumstances, groundwater capture is governed by an old English doctrine known as the Rule of Capture.
What is the Rule of Capture?
Set up in the aftermath of a state court's decision in 1904's Houston & Texas Central Railroad Company v. East, the Rule of Capture is among the most important and divisive Texan water-use laws. In sum, the rule states that a given landowner has the right to any and all groundwater that he or she can extract from his or her land. In Texas's drier counties, this has set up something of an arms race between large, well-heeled landowners who can absorb the cost of installing deep, sophisticated pumping systems.
It's worth noting that Texas is the only "arid" state that continues to use the Rule of Capture. In other parts of the western United States, this rule has caused obvious misery for small-scale landowners and may have accelerated the depletion of key aquifers during the droughts of the early 20th century.
Pertinent Groundwater Regulations
To be fair, Texas has since modified the Rule of Capture to avoid wanton resource depletion and other unintended consequences. Passed by a popular vote, 1917's Conservation Amendment permitted the state legislature to pass laws that restricted or circumscribed water use during periods of drought or in cases of clear-cut abuse. Several court decisions in the 1970s and 1980s established precedent for setting aside the Rule of Capture for large landowners who knowingly diverted water resources from neighbors for the purposes of influencing their behavior or driving them off their land.
Pertinent Surface Water Regulations
Surface water has a quieter legal history. Generally speaking, surface water use is governed by the Water Rights Adjudication Act. Since 1969, Texan landowners have been required to apply for special water-use permits before taking advantage of water resources on or adjacent to their properties. Recent droughts have made these permits particularly important.
Drainage Water and Other Issues
Storm runoff and floodwaters are lumped together as "drainage water." When these waters flow outside the bounds of a river, creek, lake or dry watercourse, they are considered to be the "common enemy" of the landowners that they affect. As long as they don't permanently divert, capture or store drainage water for private use, landowners can take steps to protect dry property from potentially damaging flows. This may include erecting temporary barricades or pumping pooled water into a nearby pond or lake.
Final Thoughts
For many Texans, groundwater use is a fraught topic. Too many landowners fail to account for the often strict, occasionally contradictory regulations that govern water use in this great state. This article should serve as a starting point for those who wish to remain on the right side of the law and maintain good relations with their neighbors.
*Image courtesy of freedigitalphotos.net
