Exhibit 18.1


August 12, 2002


Board of Directors
Waters Corporation
34 Maple Street
Milford, MA 01757

Dear Directors:

We are providing this letter to you for inclusion as an exhibit to your Form
10-Q filing pursuant to Item 601 of Regulation S-K.

We have been provided a copy of the Company's Quarterly Report on Form 10-Q for
the period ended June 30, 2002. Note 3 therein describes a change in accounting
principle from a method of capitalizing patent litigation costs to a method of
expensing patent litigation costs. It should be understood that the
preferability of one acceptable method of accounting over another for treatment
of patent litigation costs has not been addressed in any authoritative
accounting literature, and in expressing our concurrence below we have relied on
management's determination that this change in accounting principle is
preferable. Based on our reading of management's stated reasons and
justification for this change in accounting principle in the Form 10-Q, and our
discussions with management as to their judgment about the relevant business
planning factors relating to the change, we concur with management that such
change represents, in the Company's circumstances, the adoption of a preferable
accounting principle in conformity with Accounting Principles Board Opinion No.
20.

We have not audited any financial statements of the Company as of any date or
for any period subsequent to December 31, 2001. Accordingly, our comments are
subject to change upon completion of an audit of the financial statements
covering the period of the accounting change.

Very truly yours,


/s/ PricewaterhouseCoopers LLP
PricewaterhouseCoopers LLP