OPINION OF THE COURT
McDERMOTT, Justice.This case arose from the denial by the Zoning Board of Adjustment of the City of Pittsburgh of appellee’s request to occupy the property she leases in Pittsburgh as a boarding house. That decision, as affirmed by the Court of Common Pleas of Allegheny County, was based upon the fact that appellee’s property is located in an R-4 residential district where under § 937.02 of the Pittsburgh Code boarding homes are not permitted. The Commonwealth Court,1 however, reasoned that boarding homes could not be rationally excluded from the R-4 residential districts when rooming houses were allowed in such districts. Therefore, that court held § 937.02 of the Pittsburgh Code to be unconstitutional as violative of the equal protection of the law. We now reverse.
Initially, we note that zoning classifications are largely within the judgment of the legislative body and the exercise of that judgment will not be interfered with by the courts except where it is obvious that the classification has no substantial relationship to public health, safety, morals or general welfare. National Land and Investment Co. v. Easttown Township Board of Adjustment, 419 Pa. 504, 215 A.2d 597 (1965); Glorioso Appeal, 413 Pa. 194, 196 A.2d 668 (1964). In addition, when the constitutionality of a zoning ordinance is attacked, there is a presumption that the ordinance is valid and that the municipal legislative body acted with the purpose of serving the public welfare. The burden is on the challenger to rebut this presumption and prove that the ordinance in question is clearly unconstitutional. Schubach v. Silver, 461 Pa. 366, 336 A.2d 328 (1975); Bilbar *227Construction Co. v. Board of Adjustment, 393 Pa. 62, 141 A.2d 851 (1958).
In the instant case, it is clear that the legislative body of the City of Pittsburgh has classified rooming and boarding houses as different entities for zoning purposes. Section 903.02(b) of the Pittsburgh Code provides,
“ ‘Boarding house’ means a building or portion thereof, other than a hotel, containing not more than one dwelling unit, if any, where meals and lodging are provided for persons not residing in the dwelling unit.” (Emphasis added)
And, Section 903.02(r) notes,
“ ‘Rooming house’ means a building or portion thereof other than an apartment hotel or a hotel, containing not more than one dwelling unit, if any, where lodging is provided without meals for persons not residing in the dwelling unit.” (Emphasis added)
Despite this meal-service distinction, the Commonwealth Court found no real difference relevant to zoning purposes between the boarding and rooming house. In doing so, they relied primarily upon the testimony of Mr. Brown, a city zoning administrator who noted: “A boarding home, in the general sense, where people merely live there, it’s their place of residence and have at least one meal a day provided to them, I don’t see much difference between that and a rooming house.” (N.T. 12, 9/4/80)
We do not find Mr. Brown’s testimony sufficient to rebut the presumption in favor of the constitutionality of the ordinance, nor do we find that the classification distinction between boarding and rooming houses fails to bear a substantial relationship to the health, safety, morals or general welfare of the community. Rather, the record reveals that the legislature’s purpose in making a distinction between these entities was to exclude commercial institutions from residential districts.2 Within this design, a distinction *228based upon the availability of meal service — a service which necessarily invokes the city’s health code — is sufficiently related to the health, safety and general welfare of the community, so as not to offend the equal protection clause of our constitution. The zoning power is one of the tools of government which, in order to be effective, must not be subjected to judicial interference unless clearly necessary. National Land and Investment Co., supra.
For the reasons stated, we do not find it necessary to set aside the determination of the local legislative body in this case.
Therefore, the order of the Commonwealth Court is reversed.
' NIX, J., files a dissenting opinion in which LARSEN, J., joins. FLAHERTY, J., files a separate dissenting opinion.. Layne v. Zoning Board of Adjustment, 64 Pa.Cmwlth. 258, 439 A.2d 1311 (1982).
. Mr. Brown, the zoning administrator, testified:
*228Well, the rationale was set up before my time, some time between 1950 and 1958, and as I gather, through the years, the difference they had in mind at the time was that a boarding house appeared or was more of a commercial use since it’s usually more of a transient trade, and you’re feeding people, something of a restaurant type use, and for that reason they placed a boarding home in a commercial district. (Emphasis added).