The State Water Board designated the Tule Subbasin probationary on September 17, 2024, and the reporting machinery is now fully running. We first wrote about California’s groundwater sustainability requirements in 2018; here is where probation actually lands on well owners.

What is required

• Monthly measurement of groundwater extraction by all non-exempt extractors, in effect since January 1, 2025.
• Certified flow meters — or an approved evapotranspiration methodology — for pumpers above 500 acre-feet per year, required since March 1, 2025. Flow meters meeting state standards are required in the Friant-Kern Canal subsidence area.
• Annual extraction reports. The first reports, covering calendar year 2025, were due May 1, 2026; subsequent reports are due February 1 each year.
• Fees of $300 per well annually plus $20 per acre-foot, with a 25% penalty for late filing.
• Small domestic users at or below 2 acre-feet per year, and some pumpers at or below 20 acre-feet away from the Friant-Kern Canal, may be excluded.

The board adopted a minimal-impact exclusion resolution on April 7, 2026, and denied exclusion requests from eight groundwater sustainability agencies on April 21, 2026 — so probation, and its reporting, continues.

What it means in the field

Monthly numbers mean either a lot of site visits or instrumentation that reports on its own. For depth-to-water, see water level meters and level loggers and pressure transducers; for volumes, flow measurement; and for unattended stations that push data to the cloud between visits, telemetry and remote monitoring.

Sources: State Water Board — Tule Subbasin; State Water Board — What is state intervention?