There is no single Treasure Valley irrigation shutdown date. The date depends on the provider, canal or lateral, pressure system, subdivision or HOA, repairs, and water availability. The verified 2026 notices below include September 28 for Boise Project, New York Irrigation District, and Nampa & Meridian Irrigation District—and a conditional October 1–15 window for Caldwell Municipal Irrigation District.
Short answer: identify who delivers irrigation water to your property before you plan winterization. A city name is not a provider, and a seasonal irrigation shutdown is not a drinking-water outage.
First, identify your irrigation provider
The controlling question is “who delivers irrigation water to this property?” rather than “which city is the property in?” Start with the source that matches your system:
- Boise: use the City of Boise pressure-irrigation address lookup and district contact table. Selected city-operated subdivisions have different operating responsibilities from canal deliveries.
- Meridian: use the City of Meridian district map or ask your HOA. The city says most pressurized systems are not city-owned or city-operated.
- Caldwell: compare your subdivision with the City of Caldwell’s CMID communities list and check your annual irrigation bill. Properties outside CMID need another provider.
- Nampa: use the City of Nampa Waterworks contact for municipal pressurized-system questions, then confirm the upstream district where applicable.
- Any Treasure Valley address: use the IWRRI Treasure Valley irrigation-district lookup as a supplemental map, then confirm the current notice with the provider.
Best proof: your annual irrigation assessment or bill usually names the provider. A subdivision map, HOA, pump-station sign, or district office can confirm the system when the bill is not available.
2026 provider status
These are provider-specific notices, not citywide predictions. “Pending” means a current end date was not found on the official page checked; it is not permission to reuse a prior-year date.
| Provider or system | Applicable-area evidence | 2026 announced status | Normal or conditional window | Official notice / contact | Last checked |
|---|---|---|---|---|---|
| Boise Project Board of Control | Division contacts include Boise, Kuna, Lake Lowell, and Wilder. Confirm the property with the district or subdivision. | Sept. 28, 2026 for Arrowrock Division lands and Lake Lowell deliveries. | Not a universal annual window on the current notice. | Boise Project notice and contacts | Sept. 5, 2026 |
| New York Irrigation District | Serves areas in Ada and Canyon counties; confirm against the district map or office. | Sept. 28, 2026 (“WATER OFF—MONDAY SEPT 28, 2026”). | No general annual window captured on the current homepage. | NYID notice; water emergency 208-342-5086 | Sept. 5, 2026 |
| Nampa & Meridian Irrigation District | Serves agricultural and residential lands, including subdivisions, in Ada and Canyon counties. | Starting Sept. 28, 2026. | Startup and delivery can vary while flows are filled and tested. | NMID notice and contact paths | Sept. 5, 2026 |
| Caldwell Municipal Irrigation District | Use the CMID communities list and annual irrigation bill. | Not a firm 2026 announcement. | Anticipated Oct. 1–15, subject to water availability. | City of Caldwell irrigation page; 208-455-3070, option 2 | Sept. 5, 2026 |
| Settlers Irrigation District | District, lateral, watering schedule, or HOA may control the property system. | Date not found on page checked. Verify with Settlers or your HOA. | Current season information is published, but no confirmed shutdown date here. | Settlers news and contacts | Sept. 5, 2026 |
| Pioneer Irrigation District | Parts of Canyon County and western Ada County; use its map and subdivision list. | Date not found on page checked. Do not reuse a prior-year date. | No fixed general end date found on the current page. | Pioneer map and contact; 208-459-3617 | Sept. 5, 2026 |
| City of Nampa municipal pressurized system | City crews operate or test parts of the system; upstream district responsibility may differ. | Date not found on page checked. Check current service status. | Season length and temporary commissioning or repair outages vary. | Nampa irrigation page; Waterworks 208-468-5860 | Sept. 5, 2026 |
| Boise selected pressure-irrigation systems | Subdivision and address-specific; use Boise’s lookup and district contacts. | Date not found on page checked. The page said irrigation was on for 2026. | Schedule varies by named subdivision and provider. | Boise pressure irrigation | Sept. 5, 2026 |
| Meridian subdivision systems | Use the city district map or HOA; provider and operator are often separate. | Date not found on page checked. | Approx. Apr. 15–Oct. 15 is a planning reference, not a 2026 notice. | Meridian irrigation page | Sept. 5, 2026 |
| Eagle, Kuna, and Star systems | Provider varies: named districts, city systems, HOAs, and canal entities may all be involved. | Date not found on pages checked. Verify at the property level. | Pending direct primary-source confirmation. | Eagle resources; Kuna; Star | Sept. 5, 2026 |
What “water off” means
A provider shutdown means the named irrigation entity has stopped or will stop delivery to the named system. It does not mean every property in the municipality is dry, and it does not disconnect drinking water.
- District or canal delivery: the source entity’s delivery ends; laterals and parcels may experience timing differences.
- Pressurized pump system: a district may supply water while a city, HOA, or subdivision operates the pump station.
- Homeowner valve or timer: your controller and customer-side equipment still need to be shut down or winterized according to the equipment and HOA instructions.
- Drinking water: potable water is separate. Never treat an irrigation cutoff as a drinking-water outage.
Prepare before irrigation ends
- Confirm the provider and read its latest official notice.
- Turn off or winterize your controller according to provider, HOA, and equipment instructions.
- Drain or protect exposed customer-side components when the provider or HOA calls for it.
- Before spring startup, check filters, valves, backflow equipment, leaks, and pressure. CMID specifically notes maintenance and pump/pressure issues.
- Do not substitute drinking water without checking local rules and cost implications.
If water stops unexpectedly
Check the provider or HOA notice first, then use the district, city, or Waterworks outage contact. A temporary repair, pump issue, lateral cutoff, and seasonal shutdown can look similar at a sprinkler head. Do not report a seasonal irrigation cutoff as a drinking-water outage.
Frequently asked questions
Does my city determine the shutdown date?
No. Your irrigation provider and the system serving your property determine the date. City limits are not a reliable substitute for a district, canal, HOA, or subdivision lookup.
Is irrigation water drinking water?
No. Pressure irrigation and potable water are separate systems. Follow the provider’s instructions and never assume an irrigation line is safe to drink from.
Why does my neighbor still have water?
They may use another district, lateral, HOA pump station, or city-operated pressure system. They may also be seeing residual pressure or a different phase of a provider shutdown.
Can weather or water supply change the date?
Yes. Conditional windows, repairs, supply, and system operations can change timing. The official provider notice controls.
Last checked: September 5, 2026. Update owner: Website Content / PM, with seasonal source verification by City Tester. Provider notices control; this reference is not a valley-wide declaration.