Do you have a laundry room?
Yes, they have a laundry room. I believe that it's $2 per load, $2 per dry, and $2 for the detergent. There is a laundromat close to the hotel. Prices are less expensive and you can run multiple loads. That area is pretty safe, and I do my laundry at night.
Get an answer from Hyatt Place Ontario / Rancho Cucamonga staff and past guests.