Accounting Policies (Policies)	3 Months Ended
Mar. 28, 2021
Accounting Policies
Basis of Presentation	The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included in the Watts Water Technologies, Inc. (the Company) Consolidated Balance Sheet as of March 28, 2021, the Consolidated Statements of Operations for the first quarters ended March 28, 2021 and March 29, 2020, the Consolidated Statements of Comprehensive Income for the first quarters ended March 28, 2021 and March 29, 2020, the Consolidated Statements of Stockholders’ Equity for the first quarters ended March 28, 2021 and March 29, 2020, and the Consolidated Statements of Cash Flows for the first quarters ended March 28, 2021 and March 29, 2020. The consolidated balance sheet at December 31, 2020 has been derived from the audited consolidated financial statements at that date. The accounting policies followed by the Company are described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. The financial statements included in this report should be read in conjunction with the consolidated financial statements and notes included in the Annual Report on Form 10-K for the year ended December 31, 2020. Operating results for the interim periods presented are not necessarily indicative of the results to be expected for the year ending December 31, 2021, and may be further impacted by the effects of the Coronavirus Disease 2019 (“COVID-19”) global pandemic. The Company operates on a 52-week fiscal year ending on December 31, with each quarter, except the fourth quarter, ending on a Sunday. Any quarterly data contained in this Quarterly Report on Form 10-Q generally reflect the results of operations for a 13-week period.
Estimates	Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The COVID-19 pandemic has created significant uncertainty in the global economy. There have been no comparable recent events that provide guidance as to the effect COVID-19 as a global pandemic may have, and, as a result, the ultimate impact of COVID-19 and the extent to which COVID-19 continues to impact the Company’s business, results of operations and financial condition will depend on future developments, which are highly uncertain and difficult to predict. We are not aware of any specific event or circumstance that would require updates to the Company’s estimates or judgments or require the Company to revise the carrying value of the Company’s assets or liabilities as of the date of issuance of this Quarterly Report on Form 10-Q. These estimates may change as new events occur and additional information is obtained. Actual results could differ from those estimates.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In December 2019, the FASB issued ASU No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” This ASU simplifies the accounting for income taxes by clarifying and amending existing guidance related to the recognition of franchise tax, the evaluation of a step up in the tax basis of goodwill, and the effects of enacted changes in tax laws or rates in the effective tax rate computation, among other clarifications. The effective date for adoption of this ASU is the calendar year beginning January 1, 2021 with early adoption permitted. The Company adopted this standard in the first quarter of 2021, and it did not have a material impact on the Company’s financial statements. Accounting Standards Updates In March 2020, the FASB issued ASU 2020-04, "Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting." The amendments provide optional guidance for a limited time to ease the potential burden in accounting for reference rate reform. The new guidance provides optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. The amendments apply only to contracts and hedging relationships that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. These amendments are effective immediately and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. The Company is currently evaluating its contracts and the optional expedients provided by the new standard.
Shipping and Handling	Shipping and Handling Shipping and handling costs included in selling, general and administrative expenses amounted to $15.4 million and $14.0 million for the first quarters of 2021 and 2020, respectively.
Research and Development	Research and Development Research and development costs included in selling, general and administrative expenses amounted to $10.9 million and $11.5 million for the first quarters of 2021 and 2020, respectively.

Accounting Policies (Policies)

3 Months Ended

Mar. 28, 2021

The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included in the Watts Water Technologies, Inc. (the Company) Consolidated Balance Sheet as of March 28, 2021, the Consolidated Statements of Operations for the first quarters ended March 28, 2021 and March 29, 2020, the Consolidated Statements of Comprehensive Income for the first quarters ended March 28, 2021 and March 29, 2020, the Consolidated Statements of Stockholders’ Equity for the first quarters ended March 28, 2021 and March 29, 2020, and the Consolidated Statements of Cash Flows for the first quarters ended March 28, 2021 and March 29, 2020.

The consolidated balance sheet at December 31, 2020 has been derived from the audited consolidated financial statements at that date. The accounting policies followed by the Company are described in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. The financial statements included in this report should be read in conjunction with the consolidated financial statements and notes included in the Annual Report on Form 10-K for the year ended December 31, 2020. Operating results for the interim periods presented are not necessarily indicative of the results to be expected for the year ending December 31, 2021, and may be further impacted by the effects of the Coronavirus Disease 2019 (“COVID-19”) global pandemic.

The Company operates on a 52-week fiscal year ending on December 31, with each quarter, except the fourth quarter, ending on a Sunday. Any quarterly data contained in this Quarterly Report on Form 10-Q generally reflect the results of operations for a 13-week period.

Estimates

Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The COVID-19 pandemic has created significant uncertainty in the global economy. There have been no comparable recent events that provide guidance as to the effect COVID-19 as a global pandemic may have, and, as a result, the ultimate impact of COVID-19 and the extent to which COVID-19 continues to impact the Company’s business, results of operations and financial condition will depend on future developments, which are highly uncertain and difficult to predict. We are not aware of any specific event or circumstance that would require updates to the Company’s estimates or judgments or require the Company to revise the carrying value of the Company’s assets or liabilities as of the date of issuance of this Quarterly Report on Form 10-Q. These estimates may change as new events occur and additional information is obtained. Actual results could differ from those estimates.

Recently Adopted Accounting Standards

Recently Adopted Accounting Standards

In December 2019, the FASB issued ASU No. 2019-12, "Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes.” This ASU simplifies the accounting for income taxes by clarifying and amending existing guidance related to the recognition of franchise tax, the evaluation of a step up in the tax basis of goodwill, and the effects of enacted changes in tax laws or rates in the effective tax rate computation, among other clarifications. The effective date for adoption of this ASU is the calendar year beginning January 1, 2021 with early adoption permitted. The Company

adopted this standard in the first quarter of 2021, and it did not have a material impact on the Company’s financial statements.

Accounting Standards Updates

In March 2020, the FASB issued ASU 2020-04, "Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting." The amendments provide optional guidance for a limited time to ease the potential burden in accounting for reference rate reform. The new guidance provides optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships and other transactions affected by reference rate reform if certain criteria are met. The amendments apply only to contracts and hedging relationships that reference LIBOR or another reference rate expected to be discontinued due to reference rate reform. These amendments are effective immediately and may be applied prospectively to contract modifications made and hedging relationships entered into or evaluated on or before December 31, 2022. The Company is currently evaluating its contracts and the optional expedients provided by the new standard.

Shipping and Handling

Shipping and Handling

Shipping and handling costs included in selling, general and administrative expenses amounted to $15.4 million and $14.0 million for the first quarters of 2021 and 2020, respectively.

Research and Development

Research and Development

Research and development costs included in selling, general and administrative expenses amounted to $10.9 million and $11.5 million for the first quarters of 2021 and 2020, respectively.