is 20 days: 20 working days or 20 calendar days? We have never worked for a developer before and began work on a project that the City of Riverside owns. We never filed a preliminary notice as we are used to dealing with city and utility company and have never had a problem with payments. This developer is now balking at paying us. It has been 20 calendar days since we completed our portion of the work, but not 20 working days. Is it too late to file preliminary notice?