It appears that this credit can not be earned if a project does not meet some water demand through nonpotable sources. Can anyone confirm if not only consideration but actual use of nonpotable water must be implemented to earn the Integrative Process credit?

In general the credit language suggests it is more about process than prescriptive solutions. Page 47 of the Reference Guide says:

"Assess and quantify how potential nonpotable supply sources can be used to o"set potable water use for the water demands calculated above. Identify at least one on-site nonpotable water source that could supply a portion of at least two demand components."

But page 51 the Reference Guide states:

"This credit also requires that at least one on-site nonpotable water supply source contribute to at least two water demands; for example, a nonpotable water supply source such as harvested rainwater used for both irrigation and toilet flushing satisfies this requirement."