Where the 2010 ADA Standards apply, 100% of drinking fountains must comply with criteria for accessible drinking fountains found at Section 602. Of those, 50% must have spout outlets located 36 inches maximum AFF to provide access for individuals in wheelchairs (ADA Section 602.4). The remaining 50% must have spout outlets between 38 and 43 inches AFF to provide access for standing persons (ADA Section 602.7). A Hi-Lo drinking fountain satisfies requirements for both standing (Hi) and seated (Lo) persons.
Where there are an odd number of drinking fountains, the odd numbered drinking fountain is permitted to comply with criteria for seated or standing persons. For example, if there are a total of 9 drinking fountains; 4 can comply with criteria for seated persons, 4 can comply with criteria for standing persons, and the 9th one can comply with criteria for either seated or standing persons. As always, be sure to check local code requirements that apply in addition to the 2010 ADA Standards.