My water bill jumped 30% last year until I switched to the dishwasher... and it's not just dishes. I see the same pattern with shorter showers instead of baths, the meter barely moves now. We cling to these old habits thinking they save money, but the math shows otherwise... modern appliances are just more efficient sometimes.
My buddy was convinced hand washing saved more until his meter got checked for a leak that wasn't there. The guy pointed out his ten minute pre-rinse routine before the dishes even hit the sink. Turns out he was using a crazy amount of hot water just getting ready. Once he started using the dishwasher's eco cycle, his next bill dropped by a solid chunk. It really made him question all those little habits that add up without you noticing.
A thirty percent jump sounds wild, but is that actually typical for most homes? It probably depends heavily on your local water rates and how you used to wash. For a lot of folks, the difference just isn't that big a deal.