Is Irrigating a Half Acre From a Well Now a Thing of the Past? Senate Bill 1083a and IDWR's Interpretation
- Parker Stevens
- Aug 21, 2025
- 6 min read
Updated: Aug 28, 2025
Idaho Senate Bill 1083a was signed into law by Governor Little on March 20th, 2025 and took effect officially on July 1st 2025. The bill covers multiple topics but today we are focusing on how it revises certain statues surrounding the domestic use exemption for ground water wells more specifically within subdivisions. Idaho department of water resources is the executive branch tasked with interpreting and implementing the bill. On June 25th of this year, the department released an "Administrator's Memorandum" detailing their interpretation and intent on implementing the bill. In this article I intend to cover that interpretation and what it means for owners of lots within subdivisions where the primary plan for irrigation is to use a domestic well.
Disclaimer: This article is meant to be purely informative in nature and should not be taken as legal advice or a legal interpretation IN ANY WAY. The views and opinions expressed here are those of the author and represent the author's personal understanding and opinions of the changes that have taken place.
Prior to the bill...
Prior to the bill passing, any property owner with a lot could apply for and drill a well for their home. With this well, they could do whatever was necessary to residential life essentially, within reason and volume standards (up to 13,000 gallons per day). This included being able to irrigate up to one half acre of ground on a domestic well WITHOUT having to obtain a recorded water right. A significant portion of building lots developed within the state were developed with the idea of utilizing this "domestic use exemption" as the only method of irrigation.
Well use now limited to in-home use only
According the the administrator's memorandum, Idaho Code 42-2227 now states that if a proposed domestic use is (1) within a subdivision as defined in Chapter 13, Title 50 and (2) within an area where ground water development is restricted (moratorium area, groundwater management area, critical groundwater area), then the domestic use exemption is limited to "in-home use. This applies only to new wells being drilled or being used for the first time July 1st 2025 or later.
What is "in-home" use you may ask? Essentially it is just the use of water within the walls of your home. This may be cooking, cleaning, bathing, etc. Further the administrator's memorandum states that if a property owner intends to use groundwater for irrigation of a lawn, garden, landscaping, etc., then the property owner must obtain a recorded water right authorizing such use.
As touched on in the proceeding section, a significant portion of developments here in the upper snake river plain have been developed with the intention of future homeowners irrigating off of their domestic well. This is no longer allowed.
You may think, wait, surely this applies only to newly developed subdivisions? WRONG. This applies to all subdivisions within a moratorium area, groundwater management area, or critical groundwater area REGARDLESS of how long the subdivision has been platted. Below you can see on the map that that essentially covers the entire upper snake river plain. Property owners that have bought lots within these divisions are essentially out of luck when it comes to being able to have a lawn or garden unless they can somehow acquire a groundwater right. And honestly, good luck with that because the value of groundwater rights are sure to skyrocket in value with the skyrocketing demand for them due to this bill and IDWR's interpretation.
If I have well that I had drilled prior to July 1st but have not built yet, does this apply to me?
It depends. If you simply had the well drilled but have not yet used it then yes this applies to you and that well CANNOT be used for irrigation without first obtaining a groundwater right.
Additionally, if the property is NOT in a subdivision then this change does not apply to you. This is only for properties within subdivisions.
See scenario 11 provided in the section below for the example given in the memorandum addressing this situation.
Some scenarios given in the administrator's memorandum
Scenario 1: Sunbeam Subdivision is in Jefferson County, which is within the Amended
Snake River Moratorium area. The subdivision plat was approved in 2015 for 100 lots,
each lot encompassing one acre of land. The developer expected each lot owner to drill
their own individual domestic well and develop their own domestic use and
corresponding water right. As of July 1, 2025, homes had been constructed on half of
the lots in the subdivision. On August 1, 2025, Curry drills a domestic well for a home
on his lot in the subdivision. Curry intends to irrigate ½ acre of landscaping from his
domestic well. Does Curry’s proposed use require a recorded water right?
Response 1: Curry’s proposed well site is in a subdivision and is within an area with
restrictions on ground water development. Pursuant to Idaho Code § 42-227(4), Curry
may divert water for domestic use from the well without applying for a water right. The
exempt domestic use, however, would be limited to in-home use and stockwater. Any
diversion of water from the Curry well for irrigation would negate the exemption and
trigger the requirement to apply for a water right or otherwise obtain a water right.
Scenario 11: Neptune Subdivision is a twenty-lot subdivision in Twin Falls County, which is within the Amended Snake River Moratorium area. The original developer for Neptune Subdivision intended for each lot owner to drill their own domestic well and develop their own exempt domestic use. Bellingham owns a lot in the subdivision. Because he is aware of the changes to the domestic laws, Bellingham hires a well drilling company to construct a well on his property on June 30, 2025, one day prior to 6 As noted above, the Department is aware of interest in amending Idaho Code § 42-111(1)(b) to only refer to the volume limit set forth in Idaho Code § 42-111(1)(a)(ii) (2.8 acre-feet per year). Guidance for Implementing Revised Statutes for Domestic Uses - Page 12 the change in statute. Bellingham does not construct a home on the property until May 2026 and does not use any water from the well until the home is constructed. Bellingham plans on using water from the well for in-home domestic use and to irrigate ¼ acre of landscaping around his home. Does Bellingham’s proposed use require a recorded water right?
Response 11: Bellingham’s well is in a subdivision and is within an area with restrictions on ground water development. The fact that Bellingham’s well was constructed on June 30, 2025, is of no consequence. An exempt domestic use is developed the day the water begins to be beneficially used. Although Bellingham’s well was constructed prior to July 1, 2025, his domestic use was not established until May 2026. Pursuant to Idaho Code § 42-227(4), Bellingham may divert water for domestic use from the well without applying for a water right. The exempt domestic use, however, would be limited to in-home use and stockwater. Any diversion of water from the Bellingham well for irrigation would negate the exemption and trigger the requirement to apply for a water right or otherwise obtain a water right.
How does this interpretation vary from the intent of the bill?
According to Paul Arrington, Idaho Water Users Association executive direction and general counsel, in an interview with the Post Register, the IDWR's interpretation vastly differs from the bill's intent. "The intent of the bill was only to apply it to new developments," Arrington said. "It's not what we intended."
According the the Post Register article, Arrington expects that new language clarifying this intent and fixing the issue will be passed and signed into law by the first monday after New Year's Day.
For the sake of countless property owners whose property values were plummeted in this regulatory taking, I hope he is right.
If you have questions regarding what this means for you and how it affects all things real estate in Southeast Idaho, then give me a call at (208) 281-7258. Or to receive future similar articles, text SUBSCRIBE to (208) 281 - 7258.
You can read the full 17 page Administrator's Memorandum by clicking the link here:
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