The Snake River Valley's irrigation season runs from May through October, delivering water to more than 500,000 acres of agricultural land across eastern Idaho. For homeowners in Idaho Falls, Ammon, Rexburg, and surrounding communities, this seasonal shift does more than feed crops — it raises the baseline moisture conditions every home in the region has to manage.
Irrigation season isn't a reason to panic, but it is a reason to be attentive. Here's what the seasonal change means for your home and what you can do to prevent water damage before it starts.
Why Irrigation Season Increases Moisture Risk
When agricultural fields surrounding the Snake River Plain are actively irrigated, the water table in Bonneville, Madison, Jefferson, and Bingham counties rises measurably. This elevated groundwater is one reason why crawl space moisture issues tend to peak during summer rather than winter — even though winter is traditionally when people worry most about water damage.
The irrigation infrastructure itself creates additional risk. The extensive network of canals, laterals, and headgates managed by local irrigation districts doesn't always behave perfectly. Canal overflow events, broken headgates, and over-application on neighboring fields have all been sources of unexpected water intrusion for Idaho Falls homes near the canal network.
Inspect Your Crawl Space Before June
The single most protective step a homeowner can take before irrigation season begins is a crawl space inspection. Specifically:
- Vapor barrier condition: Is your vapor barrier intact, properly overlapped, and secured at the perimeter? A degraded or torn barrier allows moisture to migrate freely from the soil into the crawl space.
- Ventilation: Are crawl space vents open and unobstructed? During irrigation season, passive ventilation helps move humid air through rather than letting it accumulate.
- Drainage: Does water pool anywhere in or around the crawl space after rain? Standing water in a crawl space evaporates slowly and keeps humidity elevated for weeks.
- Mold: Any visible mold growth from last year should be addressed before irrigation season amplifies conditions.
If you find deteriorated vapor barriers or evidence of past moisture intrusion, addressing these before May is far less expensive than d



