This appeal poses the single determinative question: Does the complaint state facts sufficient to constitute a cause of action? If the answer be in the negative the ruling and judgment of the trial judge was correct; while if the answer be in the affirmative the ruling and judgment of the trial judge was erroneous. We are constrained to hold that the answer is in the negative.
A demurrer admits only relevant facts well pleaded and relevant inferences of fact readily dedueible therefrom, but does not admit the conclusions of law or inferences of law contained in the complaint. Whitehead v. Telephone Co., 190 N. C., 197, 129 S. E., 602, and cases there cited.
The complaint in this action seeks only equitable relief, namely, an injunction, and the courts will not grant such relief where there is an adequate remedy at law. Our tax law provides a method to be followed by the injured taxpayer in cases where a tax levy is deemed illegal, which is to pay the tax under protest and then bring suit to recover the same, G. S., 105-406 (C. S., 7979). G. S., 156-105 (C. S., 5361), provides that drainage assessments shall be collected in the same manner as State and county taxes under the law existing at the time of the collection. Ch. 310, sec. 1715 (b), Public Laws 1939, now G. S., 105-387, provides that “No sale (of tax liens on real property) shall be delayed or restrained by order of any court of this State.” It is therefore apparent *207from the complaint itself that the alleged action of the plaintiffs is untenable, and his Honor was correct in dismissing the same.
It would also seem that his Honor was correct in sustaining the demurrer and dismissing the action for the reason that it appears from the complaint that the plaintiff seeks to restrain acts and things directed to be done by a mandamus in a suit involving the same subject matter. This action is a collateral attack by an independent suit upon a valid, final and subsisting judgment, contrary to the consistent holding of this Court. In Spencer v. Wills, 179 N. C., 175, 102 S. E., 275, it is written, at bottom of page 177: “In various decisions appertaining to the subject, we have held that parties to proceedings of this character and in reference to their lands situate within the district are estopped from questioning by independent suit the judgment establishing the district or the validity and amount of the assessments made in the cause or the matter of burdens and benefits affecting the property. These, and other like rulings, must be challenged at the proper time and in the course of the proceedings, and unless objection is successfully maintained, the parties are concluded. Craven v. Comrs., 176 N. C., 531; Lumber Co. v. Comrs., 174 N. C., 647; Griffin v. Comrs., 169 N. C., 642; Newby v. Drainage District, 163 N. C., 24; Shelton v. White, 163 N. C., 90.” And further in Newby v. Drainage District, supra, it is held that: “. . . a drainage district is a quasi-municipal corporation, and neither its existence nor the regularity of its proceedings can be collaterally impeached. ... It is elementary that the validity of such districts cannot be collaterally attacked. . . . The plaintiffs, of course, stand in the shoes of their grantors, who were parties to the proceedings for the establishment of the district, as a pendency of the proceedings is notice with respect to all lands embraced in the district. . . . The statute in terms, declares that the order of the court confirming the final report of the viewers ‘shall be conclusive and final that all prior proceedings were regular and according to law, unless they were appealed from.’ And this statutory declaration that the regularity of the proceedings shall not be subject to collateral attack is in line with the decisions of the courts and text-writers of good repute.”
The plaintiffs’ remedy, if any they have, would be by motion in the cause. A drainage proceeding is never closed, and the plaintiffs could have moved in the cause, and thereby have raised the questions set out in their complaint. Banks v. Lane, 170 N. C., 14, 86 S. E., 713; ibid., 171 N. C., 505, 88 S. E., 754; Staton v. Staton, 148 N. C., 490, 62 S. E., 596; Mann v. Mann, 176 N. C., 353, 97 S. E., 175.
We are of the opinion, and so hold, that the judgment of the Superior Court sustaining the demurrer ore tenus and dismissing the action should be affirmed for the reason that the court will not grant the equitable relief of injunction when an adequate remedy at law existed; an act *208directed by a court order in one action will not be restrained by an order in another action collaterally attacking the former; courts will not by injunction restrain a sale of tax liens on real property, and a valid, final and subsisting judgment of the Superior Court cannot be collaterally attacked.
The judgment of the Superior Court is
Affirmed.