The tag check_date=* is used:

The date should be specified using the ISO 8601 format YYYY-MM-DD.

Examples

A road that was still under construction on 2 June 2021: 

highway=construction
check_date=2021-06-02

A road under construction whose planned opening date (5 October 2021) has been checked on 2 June 2021: 

highway=construction
opening_date=2021-10-05
check_date:opening_date=2021-06-02

A postbox that still existed on 21 September 2021 but whose collection times have probably not been checked since 13 May 2021: 

amenity=post_box
collection_times=Mo-Fr 09:00
check_date=2021-09-21
check_date:collection_times=2021-05-13

Notes

  • The original idea was to use check_date=* to document the date when an object as a whole (i.e. all its tags) have last been checked. However, it was also used to indicate only a partial survey. It has then been used by StreetComplete (and possibly by others) to document the date when only its existence was last checked due to it often being impractical to check all tags of an object.[1]
  • check_date is also used as a suffix (e.g. in collection_times:check_date=* or opening_hours:check_date=*), but much less than as a prefix.[2][3]

Synonymous tags in use

There are a number of other tags in use for documenting the date of a survey or update. Apparently there is no clear consensus as yet on which tag to use. You should try to use check_date=* or other of those tags that others have already used for the same purpose to avoid creating new duplicates. Do note, however, that not all of the tags listed here mean exactly the same thing.

Deprecated tags

See also

References