Its quite hard to get distilled water. What I would suggest is De-ionized water which you can buy from any auto shop and most garages/service stations. This is basically water that has had all the impurities removed and is as closer as pure water without distilling it.
You'll also find de-ionised sold in stores for putting in steam irons. Our lab went over to de-ionised, much cheaper to produce than distilled and very nearly as pure.
(o/t @cpemma "Resistance is Voltage/Current" hahahahahahhaha who say's physists don't have a sense of humour )