Exhibit 23.1


                       CONSENT OF INDEPENDENT ACCOUNTANTS

We  hereby  consent  to the  incorporation  by  reference  in this  Registration
Statement  on Form S-8 (No.  33-54400)  of our report  dated  February 22, 2000,
relating to the financial  statements  and the financial  statement  schedule of
Ionics, Incorporated which appears in Ionics, Incorporated Annual Report on Form
10-K for the year ended December 31, 1999.

/s/PricewaterhouseCoopers LLP
Boston, Massachusetts
June 19, 2000