Exhibit 5.2

July 17, 2017

American Renal Associates Holdings, Inc.

500 Cummings Center, Suite 6550

Beverly, Massachusetts 01915

Ladies and Gentlemen:

I am the Vice President and General Counsel to American Renal Associates Holdings, Inc., a Delaware corporation (the “Company”). Solely in such capacity and without personal liability, I have acted as counsel to the Company in connection with the Registration Statement on Form S-3 (the “Registration Statement”) filed by the Company with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), relating to an aggregate of 19,017,413 shares of common stock, par value $0.01 per share, of the Company that may be sold from time to time by certain selling stockholders of the Company (the “Selling Stockholder Shares”). The Selling Stockholder Shares may be sold or delivered from time to time as set forth in the Registration Statement, any amendment thereto, the prospectus contained therein and supplements thereto pursuant to Rule 415 under the Securities Act.

I have examined the Registration Statement and the Amended and Restated Certificate of Incorporation of the Company, which has been filed with the Commission as an exhibit to the Registration Statement. I also have examined the originals, or duplicates or certified or conformed copies, of such records, agreements, documents and other instruments and have made such other investigations as I have deemed relevant and necessary in connection with the opinion hereinafter set forth. As to questions of fact material to this opinion, I have relied upon certificates or comparable documents of public officials and of officers and representatives of the Company.

In rendering the opinion set forth below, I have assumed the genuineness of all signatures, the legal capacity of natural persons, the authenticity of all documents submitted to me as originals, the conformity to original documents of all documents submitted to me as duplicates or certified or conformed copies and the authenticity of the originals of such latter documents.

Based upon the foregoing, and subject to the qualifications, assumptions and limitations stated herein, I am of the opinion that the Selling Stockholder Shares are validly issued, fully paid and nonassessable.

I am admitted to practice law in the Commonwealth of Massachusetts.

I hereby consent to the filing of this opinion letter as Exhibit 5.2 to the Registration Statement and to the use of my name under the caption “Legal Matters” in the Prospectus included in the Registration Statement.

Very truly yours,

/s/ Michael R. Costa

Michael R. Costa