In seeking a temporary or preliminary injunction, a plaintiff must establish “irreparable injury or interim harm that it will suffer if an injunction is not issued pending an adjudication of the merits.’ The court will consider
1. The likelihood of the moving party’s success on the merits;
2. The possibility of irreparable harm to the moving party if relief not granted; and
3. Extent to which the balance of hardships favors the respective parties.
White v. Davis, 30 Cal. 4th 528, 554 (2003) (also discussing public policy issues in connection with injunctions sought against governmental agencies).
“While the mere possibility of harm to the plaintiffs is insufficient to justify a preliminary injunction, the plaintiffs are ‘not required to wait until they have suffered actual harm before they apply for an injunction, but may seek injunctive relief against the threatened infringement of their rights.’” Costa Mesa City Employees Assn. v. City of Costa Mesa, 209 Cal. App. 4th 298, 305 (2012).
Cal. Code Civ. Proc. § 526 identifies the “[c]ases in which injunction may or may not be granted.” See also Cal. Code Civ. Proc. §§ 525, et seq. (“Injunctions”).
A plaintiff seeking a preliminary injunction must establish
 that he is likely to succeed on the merits,
 that he is likely to suffer irreparable harm in the absence of preliminary relief,
 that the balance of equities tips in his favor, and
 that an injunction is in the public interest.
It is well established that, to determine whether an injunction is “just and proper,” courts apply the “familiar set of four equitable factors: the movant's likelihood of success on the merits; the possibility of irreparable injury to the moving party; the extent to which the balance of hardships favors each party; and whether the public interest will be advanced by granting the preliminary relief.”
CALIFORNIA STATE COURTS
Supreme Court of California: White v. Davis, 30 Cal. 4th 528, 554 (2003).
California 2d Dist.: Integrated Dynamic Solutions, Inc. v. VitaVet Labs, Inc., 6 Cal. App. 5th 1178, 1183 (2016); People ex rel. Feuer v. Nestdrop, LLC, 245 Cal. App. 4th 664, 672, (2016); Water Replenishment Dist. of S. Cal. v. City of Cerritos, 220 Cal. App. 4th 1450, 1461-62 (2013).
California 3d Dist.: Prigmore v. City of Redding, 211 Cal. App. 4th 1322, 1333 (2012).
California 4th Dist.: Carbajal v. CWPSC, Inc., 245 Cal. App. 4th 227, 250 (2016) (requiring “a party seeking a preliminary injunction to post a bond or other undertaking to cover any damages the enjoined party may suffer if it later is determined the injunction was erroneously granted”.); SB Liberty, LLC v. Isla Verde Ass’n, Inc., 217 Cal. App. 4th 272, 280 (2013).
California 5th Dist.: Smith v. Adventist Health System/West, 182 Cal. App. 4th 729, 749 (2010).
California 6th Dist.: Oiye v. Fox, 211 Cal. App. 4th 1036, 1047 (2012), rev. denied, No. S208185, 2013 Cal. LEXIS 1994 (Mar. 13, 2013).
CALIFORNIA FEDERAL COURT
United States Supreme Court: Winter v. NRDC, Inc., 555 U.S. 7, 20 (2008).
United States Court of Appeal for the 9th Circuit: Carr v. Stelzer, No. 17-35287, 2018 WL 2041420, at *2 (9th Cir. May 2, 2018); Herb Reed Enters., LLC v. Florida Entertainment Mgmt., 736 F.3d 1239, 1247 (9th Cir. 2013).
Central District: Ramtin Massoudi MD Inc. v. Azar, No. 2:18–cv–1087–CAS(JPRx), 2018 WL 1940398, at *4 (C.D. Cal. April 23, 2018); Constr. Laborers Trust Fund for S. Cal. Admin. Co. v. Play Smart Surfacing, Inc., No. EDCV 13-00582-VAP (DTBx), 2013 WL 6007594, at *16 (C.D. Cal. Nov. 12, 2013).
Eastern District: Leskinen v. U.S. Dep’t of Agriculture, No. 2:18-cv-0453-TLN-KJN PS, 2018 WL 3014149, at *3 (E.D. Cal. June 14, 2018); Manago v. Williams, No. 2:07-cv-02290-TLN-KJN P, 2013 WL 6512896, at *4-5 (E.D. Cal. Dec. 12, 2013).
Northern District: Gonzalez v. Sessions, No. 18–cv–01869–JSC, 2018 WL 2688569, at *8 (N.D. Cal. June 5, 2018); XimpleWare Corp. v. Versata Software, Inc., No. C 13-05160 SI, 2013 WL 6405979, at *5-6 (N.D. Cal. Dec. 6, 2013).
Southern District: Arcturus Therapeutics Ltd. v. Payne, No. 18cv766-MMA, 2018 WL 2316790, at *4 (S.D. Cal. May 22, 2018); Mytee Prods. v. Shop Vac Corp., No. 13cv1610 BTM (BGS), 2013 WL 5945060, at *2-3 (S.D. Cal. Nov. 4, 2013).