Document and Entity Information	3 Months Ended
Jun. 30, 2011	Aug. 02, 2011
Document and Entity Information
Entity Registrant Name	MIDDLESEX WATER CO
Document Type	10-Q
Document Period End Date	Jun. 30, 2011
Amendment Flag	false
Entity Central Index Key	0000066004
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		15,618,317
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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