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Drought, water rights, and private wells — when your tap runs dry
If you buy a property on a private well in California, Arizona, Nevada, Colorado, Texas, or Oregon, you've inherited a complex tangle of state water-rights law that decides whether your tap stays wet during drought. Public water systems (covered by EPA SDWIS) are insulated from much of this; private-well users are NOT.
Published 2026-04-25 · Last reviewed 2026-04-26 · methodology
Two doctrines: riparian vs. prior-appropriation
Eastern US (most states east of the Mississippi): riparian doctrine. If your land touches a stream/lake, you have rights to 'reasonable use' of that water. Conflicts resolved by 'reasonable use' tests in court.
Western US (TX, OK, KS, NE, ND, SD, MT, WY, CO, NM, AZ, UT, NV, ID, WA, OR, CA, AK, HI): prior-appropriation doctrine ('first in time, first in right'). The senior water-right holder gets ALL their entitlement before junior holders get any.
California uses both: riparian (for streams) + appropriative (for diversions). Adjudicated basins (LA, Sacramento) override defaults.
What 'first in time' means in drought
If your well drilled in 1995 has water rights filed in 1995, and the senior right-holder's well drilled in 1955 (filed 1955) is in the same aquifer — the senior right gets full draw FIRST. Your share is what's left.
In severe drought, 'curtailment orders' from the state water-resources board can shut off junior rights entirely (CA 2014-2016, 2021-2022).
Domestic-use exemptions exist in some states (CO: 0-15 gpm typically exempt) but caps + water-budget rules apply.
Pre-purchase due diligence
Get the well log: state water board has on file. Shows depth, casing, static water level, pump test gpm.
Production test: hire a licensed well-driller for a 4-hour or 24-hour pump test BEFORE close. $400-$1,200; reveals real sustainable yield.
Water-rights filing: confirm the well has a filed appropriation certificate (West) or pre-1914 riparian use claim (CA streams).
Static water level history: many states (CA, AZ) track aquifer-level decline. A well 200 feet deep in 1995 may be at 350 feet today; +20 feet decline per decade in stressed basins.
Test water quality: NOT optional. EPA-method tests for nitrates, arsenic, uranium, bacteria, hardness.
Hauled-water + dry-well risk
Annual hauled-water cost (CA Central Valley 2022-2024): $200-$800/month per household when wells go dry.
Dry-well replacement: $15,000-$50,000+ to deepen or re-drill, depending on geology.
Insurance: standard homeowners DOES NOT cover dry-well replacement.
Some counties offer dry-well rebate programs in declared drought zones.
What zipradar shows
Public water systems via EPA SDWIS — see /topic/water-quality/[zip]/.
Private wells are NOT in SDWIS coverage and NOT in our 12-dimension federation.
For drought monitoring: U.S. Drought Monitor (droughtmonitor.unl.edu) updates weekly. State water-rights filings: search state water-resources board databases (CA SWRCB, AZ ADWR, etc.).
Pair drought review + water-quality check + flood zone for a full water profile pre-purchase.
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