[1] Defendant moved to dismiss plaintiffs’ action under G.S. 1A-1, Rule 12(b)(6). The trial court entered its order granting defendant’s motion based upon “. . . the pleadings, citations of law, arguments of counsel and other evidence . . .” Because matters outside the pleadings were considered by the court in reaching its decision, the motion should be treated as a motion for summary judgment and disposed of in the manner and on the conditions stated in G.S. 1A-1, Rule 56. Kessing v. National Mortgage Corp., 278 N.C. 523, 180 S.E. 2d 823 (1971).
Having converted defendant’s Rule 12(b)(6) motion into a Rule 56 motion for summary judgment, the question on appeal is whether there is a genuine issue as to any material fact. Fowler v. Williamson, 39 N.C. App. 715, 251 S.E. 2d 889 (1979). The trial court in its order refers to “other evidence” outside of the allegations in the complaint which it considered in determining that there was no genuine issue of material fact and that as a matter of law:
(3) The Defendant, City of Lenoir, had not waived said governmental immunity pursuant to N.C.G.S. 160A-485.
*610The record on appeal, however, does not contain any of the evidence relied upon by the trial court in support of its conclusion. The record on appeal contains only the bare complaint and no other pleading, deposition, affidavit or testimony. Furthermore, the complaint makes no mention of whether governmental immunity exists or is waived.
[3] We do not intimate that in the form the controversy took in the District Court that the court lacked justification for its conclusion. Nevertheless, because of the inadequacy of the record to decide the factual and legal issues involved in governmental immunity, this Court is unable to determine whether there is any genuine issue of material fact and whether summary judgment was properly granted on the evidence before the trial court. See Kennedy v. Silas Mason Co., 334 U.S. 249, 92 L.Ed. 1347, 68 S.Ct. 1031 (1948).
Had it been evident from the record that there was no waiver of governmental immunity by defendant, then it is clear plaintiffs could not prevail on their claim for the following reasons.
[2] The establishment and construction of a sewer system by a municipality are governmental functions entitling it to immunity from negligence. Metz v. Asheville, 150 N.C. 748, 64 S.E. 881 (1909). Plaintiffs concede in their brief that “. . . the maintenance of a public sewerage system is a governmental function,” citing Metz v. Asheville, supra. Plaintiffs argue that even if the doctrine of governmental immunity is applicable, property damages are recoverable, relying on Rhyne v. Mount Holly, 251 N.C. 521, 112 S.E. 2d 40 (1960). We do not agree. The case sub judice is distinguishable since plaintiffs neither allege facts sufficient to support a nuisance claim nor is their claim based on a theory of nuisance. Thus, the City of Lenoir, while performing a governmental function in the maintenance of a sewer system within its municipal jurisdiction, may not be held liable for any damage arising out of the governmental activity unless it expressly waives its immunity pursuant to N.C. Gen. Stat. § 160A-485.
[3] As stated above, because of the inadequacy of the record, the Court is unable to review the grant of summary judgment on the issue of waiver. Hence we vacate the judgment below and remand the case to the district court for amplification of the record in light of this opinion.
*611Reversed and remanded.
Judges Hedrick and Wells concur.