Waterstop Reg 31 Certificate 28.12.2016 – 27.12.2021 Posted December 12th, 2018 by Vicki Richardson & filed under . Waterstop Reg 31 Certificate 28.12.2016 - 27.12.2021 Leave a Reply Click here to cancel reply. Name (required) Mail (required) (will not be published) Website XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>