■ This suit by the taxpayers, residents in the annex to the original sewer district to the city of *406Fayetteville, challenges the validity of said annex, claiming it is, in effect, two separate improvements, because of the inclusion of two entirely separate and distinct tracts of land in one improvement and because of the excessive assessment of benefits in the annex, exceeding in proportion those authorized in the original sewer district. It is conceded that the district otherwise was duly organized and the assessment of benefits legally made.
It appears that the original Sewer District No. 1 of the city of Fayetteville included the entire area of the city at that time, and was organized in 1906, and the improvements had long since been completed before the organization of this annex. That the territory in the annex No. 1 to said sewer district includes two eig'htyacre tracts of land adjoining the north line of the orig-’ inal sewer district, which have been divided into lots and blocks, both being within the city limits, but which tracts are separated by a forty-acre tract of land between them, also adjoining the north line of the sewer distinct, but outside the city limits.
• The. testimony shows that the improvement was constructed and completed before the institution of this suit, the sewer mains in the eastern tract being built down into and connecting with the main in the original district, the sevyage being carried through the. old district, through its mains, into the mains in the western tract of the annex and on into the. septic tank constructed for the original district.
. It is true our statutes contemplate the organization of districts to construct improvements which constitute single projects, and wholly disconnected improvements cannot be joined together in one district, as said in Cooper v. Hogan, 163 Ark. 312, 260 S. W. 25. It was- also said there:
“However, this court laid down the rule, many years ago, that 'the action of a city council in including property in an improvement district is, except when attacked for fraud or demonstrable mistake, conclusive of the fact that such property is “adjoining the locality to be *407affected” by the improvement, Avithin the meaning of the Oonstitxition’.” Little Rock v. Katzenstein, 52 Ark. 107, 12 S. W. 198. “This rule necessarily implies that the determination of the city council as to the singleness and unity of the project, as Avell as the selection of the property to be benefited thereby, is conclusive, except for fraud or demonstrable mistake.”
It cannot be said here that this improvement Avas more than a single project, nor that the property Avithin either tract of the annexed territory Avas not benefited by such improvement, notwithstanding the fact that the two tracts of land Avere separated by the forty-acre tract between them. The purpose, evidently, in malring an annex to the district was to benefit the said property by connecting it xvith the mains of the old district and furnishing a complete sewerage system to the entire property included, and the city council having determined the singleness and unity of the project, as also the selection of the property to be benefited thereby, its action is conclusive. Cooper v. Hogan, supra, and cases cited.
It is next urged that the district annex is invalid because the assessment of benefits in the territory annexed is illegal, exceeding in proportion those authorized by law and levied in the original seAver district.
In Pledger v. Soltz, 169 Ark. 1125, 278 S. W. 50, this court construed the statute relating to this question, saying’: _ _ _
_ _ _ “While it is unnecessary for the petition for annexalion to specify the limitation upon the cost, we interpret Ihe statute itself to mean that the cost of the additional improA’-ement shall be limited to the proportionate cost of the original improxmment. This limitation is expressed in the statute itself, and need not be expressed in the petition of. the property OAvners. The statute (0. & M. Dig., § 5733) provides that the assessments on the annexed territory shall be made ‘on the same basis as if said territory was included in the original district.’ This means that the proportionate cost shall be the same 'as in the original district; that is to say, the cost of improvements *408shall be in the same proportion to the assessed valuation as the cost of the improvement in the original district is to the assessed valuation of the property in that district. Otherwise the assessments on the annexed territory would not be ‘ on the same basis as if said territory was included in the original district’. * * * It becomes the duty of the commissioners, under the law, to ascertain the proportionate cost of the original improvement and to limit the cost of the new improvement to the same proportion, not exceeding the same proportion to the county assessment of the property in the annexed territory for the year next preceding the formation of the original district. * * All that the annexation statute requires is that the new assessment of benefits on the added territory must be made on the same basis as the assessments in the original territory, and this is fully accomplished by limiting the cost of the new improvement in the same proportion to the assessed value of the new territory to be added, the same as the proportionate cost of the original improvement to the property in the original district.”
In Little Rock v. Boullioun, the latest expression of this court of the subject, it was said:'
“This court decided in Pledger v. Soltz, 169 Ark. 1125, 278 S. W. 50, that the percentage of the cost of the added improvement must be the same as that of the original district, otherwise the assessments would not be on the same basis as required by the.statute. Now, it is seen that this statute governing annexation, as interpreted by the court in the case just referred to, limits the maximum cost of the improvement, and of course that limit cannot be exceeded.” Little Rock v. Boullioun, 171 Ark. 245, 284 S. W. 745.
This proceeding was begun long after the expiration of the 'time allowed by law for questioning the reasonableness and legality of the assessment of benefits, the maximum cost of the improvement considered, and amounts to a collateral attack upon such assessments, which cannot be maintained unless it is shown to be void *409on the face of the proceedings, which has not been done. Bd. of Imp. v. Pollard, 98 Ark. 543, 136 S. W. 957; Reitzammer v. Desha Road Imp. Dist., 139 Ark. 168, 213 S. W. 773; Taylor v. Bd. of Commrs., 156 Ark. 226, 245 S. W. 491. The complainants not only waited until after the expiration of the time allowed by law for attacking-the assessment of benefit's directly, but for more than a year thereafter, and until after the sale of the bonds and the completion of the improvement, and, having done so, they are now without standing in a court of equity to attack its validity or to demand the relief prayed.
We find no prejudicial error in the record, and the judgment is affirmed.