While it is possible to use your Creatista Plus machine without setting the Water Hardness under Settings, it's not a good idea to skip this step. The Water Hardness setting, plus how often you make coffee, will let the machine know when to notify you that it is time to Descale AND give you a 10 coffee drinks countdown until it locks you out. Without the Water Hardness setting in place, the Creatista Plus will alert you to Descale after about 3 months and there won't be any wiggle room to delay it once it appears.