San Antonio, TX Drought Survival: What the Edwards Aquifer Record Actually Tells You

Last Updated: July 2026 | Based on FEMA, NOAA, and USGS data

Texas has recorded 32 federally declared disasters since 2016, and the breakdown tells a specific story about San Antonio’s real risk profile. Twenty of those declarations were wildfires. Four were floods. Four were hurricanes. Only two involved ice, and one was a disease outbreak. Drought doesn’t appear once as its own FEMA declaration, because drought rarely triggers the kind of sudden, visible damage that unlocks federal assistance. What it does instead is quietly drain the Edwards Aquifer, the single underground limestone formation that supplies roughly 90% of San Antonio’s drinking water, while the wildfire smoke is still clearing and the flood debris is still drying.

That’s the paradox for anyone living in Bexar County: the disasters that make the federal register are fire and flood, but the slow-moving crisis underneath them is water scarcity. The two most recent FEMA flood events in Texas hit in May and July 2025. Before that, four separate wildfires were declared in early 2026 alone. Each fire season bakes the soil, accelerates runoff during the next rain event, and ultimately delivers less water to aquifer recharge zones. Each flood arrives fast and leaves fast, with most of that water rushing off into the Gulf watershed rather than percolating down through the karst geology north of the city. You end up with both extremes, too much water at once, then not enough, and neither one refills what San Antonio actually drinks.

This guide focuses on what that cycle means for your household, and what you can do about it before a Stage 3 restriction lands in your inbox from SAWS.

The Edwards Aquifer Is the Variable You Need to Watch

The USGS monitors the Edwards Aquifer in near real-time through index wells in Uvalde and Bexar counties. When the Bexar County index well at J-17 drops below 650 feet above mean sea level, SAWS triggers Stage 1 restrictions. Below 630 feet, you’re in Stage 2. Most San Antonio homeowners have never looked up the J-17 reading in their lives, which is roughly equivalent to living in a flood zone without knowing your property’s base flood elevation.

The aquifer’s level is a direct function of recharge, and recharge is a direct function of rainfall in a specific band of Hill Country counties to the north and west. When Texas burns through fire seasons like the four FEMA-declared wildfires already on record in early 2026, that recharge corridor gets scorched. Burned soil repels water instead of absorbing it. The next rain event, like the FEMA-declared flooding in July 2026, runs off fast rather than filtering down through the Balcones Escarpment into the aquifer. San Antonio’s water utility ends up watching two disasters in sequence and emerging from both of them with a lower aquifer level than before.

Checking the J-17 level takes about 30 seconds on the USGS National Water Information System site. Build it into the same habit as checking the weekend weather.

What Wildfire Season Means for Your Water Tap

With 20 of Texas’s 32 FEMA declarations since 2016 classified as wildfires, this is the state’s defining disaster type, and it has a downstream effect on drought that most preparedness guides skip entirely. Wildfires in the Hill Country and West Texas don’t just threaten structures; they alter the hydrology of the recharge zone for years afterward.

For San Antonio households, the practical implication is this: when a significant wildfire burns through Kerr, Kendall, or Medina counties, start treating it as an early warning for aquifer stress 6 to 18 months later. That’s your window to front-load the conservation measures below before restrictions force you into them on a compressed timeline.

• ☐ Check the USGS J-17 index well reading monthly, bookmark waterdata.usgs.gov and set a calendar reminder.
• ☐ Register for SAWS WaterSaver alerts so drought stage changes reach you before the news cycle does.
• ☐ Audit your irrigation controller: most San Antonio yards can cut outdoor water use by 30–40% with a seasonal schedule adjustment alone, no hardware required.
• ☐ Replace any cool-season turf (ryegrass overseeding) with buffalo grass or other Edwards Plateau natives that go dormant instead of dying during Stage 2 restrictions.
• ☐ Install a rain sensor shutoff on your irrigation system, it’s required by Texas law for new installs and SAWS offers a rebate on retrofits.

Household Water Storage: The Numbers Behind the Recommendation

FEMA recommends one gallon per person per day as a baseline for drinking and sanitation. For a drought scenario in San Antonio, where municipal supply continues but under strict rationing, that math changes. You’re not planning for zero water; you’re planning for situations where the tap works but usage is heavily restricted, water quality notices are in effect, or a concurrent emergency (a wildfire evacuation, a boil-water order following a flood) compounds the scarcity.

A more realistic target for a San Antonio household: 14 gallons per person in stored potable water, plus a secondary collection system for non-potable outdoor use. That covers two weeks at the FEMA baseline, which aligns with the duration of most Stage 3 restriction periods and gives you buffer through a concurrent emergency.

• Potable storage: Food-grade 5- or 7-gallon jugs rotated every 6 months; store in a cool, dark location away from direct sunlight (garage temperatures in San Antonio summers can degrade container integrity).
• Water purification: Portable filter rated for bacteria and protozoa, plus calcium hypochlorite tablets, not just iodine, for municipal water that’s under a boil-water advisory during a flood recovery period.
• Rainwater collection: Texas law allows residential rainwater harvesting without a permit. Even two 55-gallon barrels connected to a downspout can cover most outdoor plant watering needs through a Stage 2 restriction period.
• Non-perishable food: Prioritize items that require no cooking water, canned goods with pull tabs, nut butters, dried fruit. Each meal that doesn’t require boiling or rinsing conserves roughly a half-quart.
• Hygiene supplies: Hand sanitizer, wet wipes, and disposable dishware reduce daily water demand by 1–2 gallons per person without any meaningful sacrifice in sanitation.
• Battery-powered radio: For NOAA Weather Radio alerts during heat advisories, the events that most often accompany severe drought and push dehydration risk into dangerous territory for elderly residents and outdoor workers.
• Prescription medications: 7-day supply minimum; dehydration-related conditions (kidney stones, UTIs) spike during drought periods and can require urgent care when you’d rather not be driving anywhere.

When Restrictions Hit: Stage-by-Stage Priorities

SAWS operates a four-stage drought contingency plan tied directly to aquifer levels. Most households only engage with it when a Stage 2 notice arrives and their HOA starts sending emails about watering days. Getting ahead of each stage by one level is the entire game.

Before Stage 1 triggers (J-17 above 660 ft): Complete your irrigation audit, install your rain sensor, and fill your stored water supply. This is maintenance mode.

During Stage 1 (J-17 at 650–660 ft): Shift to twice-weekly hand watering only on your assigned days. Run full dishwasher and laundry loads only. Fix any dripping faucets, a slow drip wastes roughly 3,000 gallons per year.

During Stage 2 (J-17 at 630–650 ft): Outdoor irrigation drops to once weekly, overnight only, for 2-hour maximum sessions. Pull your stored water into active rotation. Begin monitoring the National Weather Service San Antonio forecast daily, any heat advisory stacked on top of a Stage 2 restriction is a signal to check on neighbors who are elderly or have health conditions that increase heat sensitivity.

During Stage 3 (J-17 below 630 ft): Outdoor irrigation is essentially suspended except for hand watering of food gardens and trees. This is when your 14-gallon-per-person reserve and rainwater collection system earn their place.

Frequently Asked Questions

Texas has 20 FEMA wildfire declarations since 2016, does that actually affect San Antonio’s drinking water?

Yes, indirectly but significantly. When wildfires burn through the Hill Country counties that sit over the Edwards Aquifer’s recharge zone, they alter soil permeability for years. Subsequent rain events run off instead of percolating into the aquifer. San Antonio’s water supply doesn’t recover from a fire season the way it recovers from a single dry month. The 2026 FEMA wildfire declarations. Corner Pocket, 8 Ball, Hunggate, and Stinky fires, all in the first half of the year, are worth watching for their long-term aquifer impact.

The 2025 and 2026 FEMA flood events in Texas look severe, does flooding actually help the aquifer level?

Only partially, and less than most people expect. For the Edwards Aquifer, meaningful recharge requires water to flow over specific limestone outcrop areas in the recharge zone north of San Antonio, not everywhere in the state. The FEMA-declared flooding events in May 2025, July 2025, and July 2026 involved widespread severe storms, but flash flooding tends to move water out of the watershed quickly rather than infiltrating it slowly through karst geology. A slow, soaking rain over the recharge zone does far more for aquifer levels than an intense flash flood event.

Are there rebates for water conservation measures in San Antonio?

SAWS maintains one of the more aggressive utility rebate programs in Texas. Current offerings include rebates for high-efficiency toilets, irrigation system upgrades, weather-based irrigation controllers, and turf replacement with drought-tolerant natives. The WaterSaver Landscape Coupon program pays per square foot of grass replaced with approved xeriscape plants. Check the SAWS WaterSaver site directly for current rebate amounts, as they adjust periodically based on aquifer conditions and program funding.

Sources

This guide utilizes data from FEMA.gov, weather.gov, and the USGS.gov. This article is for informational purposes only. Always follow directives from local emergency management authorities.