The Shuishu script (also called Sui script) is not yet in Unicode. The script has a tentative allocation at U+1B300..U+1B4FF in the Roadmap to the SMP for the Unicode Standard.
A number of documents towards its inclusion have been submitted to the Unicode Technical Committee and WG2:
2015-10-22 Preliminary Proposal for encoding Shuishu in the SMP of the UCS — China N.B. (WG2 N4696 part 1, L2/15-285)
2015-10-22 Introduction of Shuishu Script — Chen Zhuang, Zhao Liming, Yao Qingjun, Wei Shifang, Yao Binglie, Pan Zhongxi (WG2 N4696 part 2, L2/15-286)
2016-09-24 Updated Proposal for encoding Shuishu in the SMP — China N.B. (WG2 N4696, L2/16-263)
Recommendations to UTC #149 November 2016 on Script Proposals ( L2/16-342) (See point 9.)
UTC #149 Minutes ( L2/16-325) (See C.7 for decision and action items)
2017-07-26 Towards the ordering of the Shuishu script in the UCS — Michael Everson (WG2 N4839, L2/17-239)