What are other health conditions that can caused increased thirst and urination besides diabetes?

DI: Diabetes insipidus prevents the kidney from holding on to water, but this is rare. A water deprivation test may be necessary to rule out if it's being considered a possible dx. Urine is always dilute in di. However, increased frequency of urination is not the same as increase in urine volume, leading to much urination. Some people just drink a lot of fluid out of habit and void a lot.