Spring storms
Flash flooding and saturated soil can trigger sudden settlement.
What the Edwards Aquifer is
The Edwards is a limestone aquifer that runs in a band along the Balcones Fault Zone, roughly following the line of the Hill Country edge through Comal County. Water enters it in the recharge zone, where the limestone is exposed at the surface or under thin soil, and flows underground toward springs and wells.
Comal Springs, in Landa Park, is one of the major outlets, and it is the reason the Comal River exists.
The EAA describes itself as a groundwater conservation district that manages and protects the aquifer, which serves roughly two and a half million people in the region. It regulates people who own Edwards wells with withdrawal permits. It does not regulate your lawn.
Who sets which rules
This is where many residents get confused. The EAA runs a Critical Period Management (CPM) plan that cuts how much permit holders may pump when the aquifer is low. Permit holders include cities and water utilities that pump Edwards water for their customers. The EAA states plainly that it does not enforce lawn watering limits; that job belongs to cities and utilities.
For most homes in town, the utility is New Braunfels Utilities. When NBU moves to a stricter conservation stage, the rules on sprinkler days and hours change for its customers. If you are served by another provider in Comal or Guadalupe County, your rules come from that provider, and they can differ from NBU's.
Our earlier post on foundation watering under NBU drought stages covers the household rules in detail.
The numbers that trigger aquifer stages
For the San Antonio Pool, which includes Comal County, the EAA's CPM chart ties each stage to 10-day averages at three points: the J-17 index well in Bexar County, Comal Springs and San Marcos Springs. Stage 1 begins when J-17 falls below 660 feet above mean sea level, or Comal Springs below 225 cubic feet per second (cfs), or San Marcos Springs below 96 cfs.
Stage 2 starts below 650 feet at J-17 or 200 cfs at Comal Springs.
The deeper stages are tied to J-17 and Comal Springs only: Stage 3 below 640 feet or 150 cfs, Stage 4 below 630 feet or 100 cfs, and Stage 5 below 625 feet or Comal flow under 45 cfs on a ten-day average. Required pumping cuts for permit holders run from 20 percent in Stage 1 to 44 percent in Stage 5.
A stricter stage starts when any one indicator crosses its line, and easing back requires all three to recover.
In August 2026 the EAA declared Stage 2 for the San Antonio Pool, effective August 6, and noted the pool had been under some stage of CPM since March 2022. Conditions change week to week, so check the EAA's current readings rather than relying on any article, including this one.
Why springflow and your slab are connected
The same dry spells that pull down J-17 and slow Comal Springs also dry out the soil around your house. East of I-35 and in much of the newer growth toward Seguin and the Guadalupe valley, homes sit on dark clay that shrinks as it loses water and swells when it gets wet again.
When watering days are cut, the soil along the slab edge dries faster than the soil in the middle, and the edge of the slab can drop.
Homes on the thin rocky soils west of town, closer to the recharge zone, react differently. Limestone close to the surface does not shrink, but the shallow soil over it can wash out at slab corners, and water from roofs and patios can run along the rock instead of soaking in.
Either way, the water you put on the ground and the water you shed from the roof both affect how the foundation behaves.
Planning a yard that works with the aquifer
Put your limited water where it does the most good. Under NBU's Stage 2 rules as announced in August 2026, handheld hoses with shutoff nozzles, buckets, drip lines and non-spraying soaker hoses could be used on any day before 10 a.m. or after 8 p.m., while sprinklers were limited to one day a week by address.
A soaker line about 12 to 18 inches from the slab edge, run on an even schedule, keeps soil moisture steadier than an occasional heavy sprinkler soak.
Group thirsty plants away from the foundation. Large shade trees, St. Augustine turf and annual beds near the slab all compete for the same water. Native and adapted plants with deep roots need far less once established, and mulched beds lose less moisture to evaporation.
Move roof water away from the house. Gutters with downspout extensions or buried outlets send water at least several feet from the foundation, which matters most on clay where water pooling at one corner causes uneven swelling. Our drainage correction work covers regrading and surface drains.
Living on or near the recharge zone
Parts of western Comal County lie over the Edwards recharge and contributing zones. The Texas Commission on Environmental Quality (TCEQ) has Edwards Aquifer rules for regulated development in these zones, mainly for subdivisions and commercial projects. For a single homeowner the practical points are simple: keep fertilizer and pesticide use light, never wash chemicals into a sinkhole or a fractured ledge, and make sure drainage changes on your lot do not channel polluted runoff into the rock.
When dry years show up in the house
If cracks in drywall over doors, sticking doors and gaps at baseboards show up during a long Stage 2 or Stage 3 summer, the cause may be seasonal soil shrink. Some of that closes when rain returns. If cracks keep widening year over year, a measured foundation inspection will show whether the slab is moving beyond normal seasonal range. More local topics are on our New Braunfels guides page.
Sources
Edwards Aquifer Authority: Critical Period / Drought Management, CPM stage chart and the August 2026 Stage 2 declaration. Community Impact, New Braunfels moves to Stage 2 drought restrictions. TCEQ, Edwards Aquifer protection program.
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