We arrive from the states on a Sunday to Zurich just after 1 pm. We will transfer via train to Luzern. My husband uses a CPAP machine and uses a sinus rinse twice a day, not using it is not an option. In Italy we found it at the pharmacy and were very lucky to have our first Airbnb buy some for us as we arrived after the pharmacy was closed. I did not know that stores are closed on Sundays when I booked our flights, whoops. The stores at the train station will be open to get groceries. Do the grocery stores at the train station in Luzern have distilled water? ( I guess also the zurich airport train station or Zurich main station grocery store could also be used. )
They should have it at Coop grocery store in the Zurich Airport
http://www.coop.ch/de.search.html#query=destilliertes%20Wasser
Details
https://www.zurich-airport.com/the-company/media/news-center/2014/dez/ac-20141208-coop-eroeffnung
in case the Zurich Coop is out of stock, there’s a Coop in the Luzern train station too. Google map shows it as open on Sundays.
ALL the shops in the Luzern train station are open EVERY DAY. That includes the pharmacy there.
(That's not the case outside the station.)
Here's the web site for more info:
https://www.sbb.ch/en/station-services/railway-stations/lucerne-station.html
Thanks so much for all the information! Looks like I can definitely find the water on the Sunday, which is great news.
Fyi--The shopping center is downstairs, below the main level of the Luzern train station. There are escalators and an elevator if you need it with your luggage.