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</LabelSeparator><Level>4</Level><ElementName>us-gaap_PartnersCapitalNotesDisclosureTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>verboseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="D2013Q2YTD_dei_LegalEntityAxis_udr_UnitedDominionRealityLPMember" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div style="font-family:Times New Roman;font-size:10pt;"&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;CAPITAL STRUCTURE&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;General Partnership Units&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The General Partner has complete discretion to manage and control the operations and business of the Operating Partnership, which includes but is not limited to the acquisition and disposition of real property, construction of buildings and making capital improvements, and the borrowing of funds from outside lenders or UDR and its subsidiaries to finance such activities. The General Partner can generally authorize, issue, sell, redeem or purchase any OP Unit or securities of the Operating Partnership without the approval of the limited partners. The General Partner can also approve, with regard to the issuances of OP units, the class or one or more series of classes, with designations, preferences, participating, optional or other special rights, powers and duties including rights, powers and duties senior to limited partnership interests without approval of any limited partners except holders of Class&amp;#160;A Partnership Units. There were &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;110,883&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; General Partnership units outstanding at &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;December&amp;#160;31, 2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, all of which were held by UDR.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;Limited Partnership Units&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;At &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;December&amp;#160;31, 2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, there were &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;184,170,370&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; limited partnership units outstanding, of which &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;1,873,332&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; were Class&amp;#160;A Limited Partnership units. UDR owned &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;174,846,993&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; or &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;94.9%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;174,775,152&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; or &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;94.9%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; at &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;December&amp;#160;31, 2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, respectively, of which &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;121,661&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; were Class A Limited Partnership units. The remaining &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;9,323,377&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; or &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;5.1%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;9,395,218&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; or &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;5.1%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; limited partnership units, were held by non-affiliated partners at &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;December&amp;#160;31, 2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, respectively, of which &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;1,751,671&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; were Class&amp;#160;A Limited Partnership units.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Subject to the Operating Partnership Agreement, the limited partners have the right to require the Operating Partnership to redeem all or a portion of the OP Units held by the limited partner at a redemption price equal to and in the form of the Cash Amount (as defined in the Operating Partnership Agreement), provided that such OP Units have been outstanding for at least &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;one&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; year. UDR, as general partner of the Operating Partnership may, in its sole discretion, purchase the OP Units by paying to the limited partner either the Cash Amount or the REIT Share Amount (generally one share of common stock of UDR for each OP Unit), as defined in the Operating Partnership Agreement.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The non-affiliated limited partners&amp;#8217; capital is adjusted to redemption value at the end of each reporting period with the corresponding offset against UDR&amp;#8217;s limited partner capital account based on the redemption rights noted above. The aggregate value upon redemption of the then-outstanding OP Units held by limited partners was &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$237.7 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$223.4 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; as of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;June&amp;#160;30, 2013&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; and &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;December&amp;#160;31, 2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, respectively, based on the value of UDR&amp;#8217;s common stock at each period end. A limited partner has no right to receive any distributions from the Operating Partnership on or after the date of redemption of its OP Units.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-style:italic;"&gt;Class&amp;#160;A Limited Partnership Units&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Class&amp;#160;A Partnership units have a cumulative, annual, non-compounded preferred return, which is equal to &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;8%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; based on a value of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$16.61&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per Class&amp;#160;A Partnership unit.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Holders of the Class&amp;#160;A Partnership Units exclusively possess certain voting rights. The Operating Partnership may not do the following without approval of the holders of the Class&amp;#160;A Partnership Units: (i)&amp;#160;increase the authorized or issued amount of Class&amp;#160;A Partnership Units, (ii) reclassify any other partnership interest into Class&amp;#160;A Partnership Units, (iii)&amp;#160;create, authorize or issue any obligations or security convertible into or the right to purchase any Class Partnership units, (iv)&amp;#160;enter into a merger or acquisition, or (v)&amp;#160;amend or modify the Agreement of Limited Partnership of the Operating Partnership in a manner that adversely affects the relative rights, preferences or privileges of the Class&amp;#160;A Partnership Units.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;Allocation of profits and losses&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-top:13px;text-align:left;text-indent:32px;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Profit of the Operating Partnership is allocated in the following order: (i)&amp;#160;to the General Partner and the Limited Partners in proportion to and up to the amount of cash distributions made during the year, and (ii)&amp;#160;to the General Partner and Limited Partners in accordance with their percentage interests. Losses and depreciation and amortization expenses, non-recourse liabilities are allocated to the General Partner and Limited Partners in accordance with their percentage interests. Losses allocated to the Limited Partners are capped to the extent that such an allocation would not cause a deficit in the Limited Partners' capital accounts. Such losses are, therefore, allocated to the General Partner. If any Partner&amp;#8217;s capital balance were to fall into a deficit, any income and gains are allocated to each Partner sufficient to eliminate its negative capital balance.&lt;/font&gt;&lt;/div&gt;&lt;/div&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>The entire disclosure for the formation, structure, control and ownership of the partnership. Disclosures related to accounts comprising partners' capital. Includes balances of general partners' capital account, limited partners' capital account, preferred partners' capital account and total partners' capital account and units outstanding; accumulated other comprehensive income; amount and nature of changes to amount of partner's capital and units outstanding by class, rights and privileges for each class of units; distribution policies and distributions paid by unit class; impact of and correction of an error in previously issued financial statements; limitations of partners' liability; redemption, conversion and distribution policies; and deferred compensation related to the issuance of units.</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Accounting Standards Codification

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Emerging Issues Task Force (EITF)

 -Number 87-21

 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 4: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

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 -Publisher AICPA

 -Name Practice Bulletin (PB)

 -Number 14

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 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.  This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



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