Water and Agriculture Tax Reform Act of 201 7 This bill amends the Internal Revenue Code to permit tax-exempt mutual ditch or irrigation companies to earn income from dispositions of certain real property and stock interests without affecting their tax-exempt status, but requires that such income be used to pay the costs of operations, maintenance, and capital improvements of such a company. The bill also establishes a rule regarding the organizational governance of mutual ditch or irrigation companies. Where state law provides that such a company may be organized in a manner that permits voting on a basis that is pro rata to share ownership on corporate governance matters, an organization's qualification as a mutual ditch or irrigation company must be determined without taking into account whether its member shareholders have one vote on corporate governance matters per share held in the corporation.