The dispute involved in this action concerns the right to the possession of a strip of land approximately 175 feet in width and a dwelling house located thereon. The plaintiff claims title by virtue of a tax deed; the defendants’ claim is based upon the contention that the taxes were paid. The essential facts are not in dispute.
The description of the land conveyed by the tax deed is the west half of the southwest quarter of the southeast quarter of the southwest quarter of section 2, township 29 north, range 6 east W. M., Snohomish county, Washington. The defendants are contract vendees of the east half of the same quarter-quarter-quarter section.'
When the east half was conveyed in 1929 by the owner of the entire quarter-quarter-quarter section, it was understood that the west boundary of the tract was a county road which ran north and south. This road was treated as the boundary by the grantor and by the grantee and his successors, to and including the defendants, A house was constructed on the tract in 1929 fairly close to the road. There are no improvements on the west half west of the county road. The defendants and their predecessors paid the taxes on the east half and on the house, which was listed by the assessor as an improvement to the east half. The original *73grantor paid the taxes on the west “half” until 1947, when she decided to abandon it for taxes because she “knew it was short.”
When the plaintiff acquired his tax deed, he had the tract surveyed and discovered that the house was situated on the west half and that, in fact, the true boundary between the east half and the west half was 175.6 feet east of the county road. He thereupon brought this ejectment action to quiet title to that portion of the west half lying east of the county road.
The trial court concluded that, since the house was taxed as an improvement to the east half, the assessor must have been laboring under the same misapprehension as the defendants and their predecessors, that the west boundary of the east half was the county road, and therefore must have assessed that portion of the west half which lay east of the county road as a part of the east half.
No issue on this appeal is made to any claim of title by adverse possession, as both parties agree that a tax foreclosure wipes out any rights acquired thereby. The plaintiff’s contention is that the defendants’ interest, however acquired, was cut off by the tax deed, and that the inference drawn by the trial court, that the taxes on the disputed land as well as on the improvements had been paid, was in error.
RCW 84.40.040 provides inter alia:
“The county assessor shall begin the preliminary work for each assessment not later than the first day of December of each year. He shall complete the duties of listing and placing valuations on all property by May 31st of each year, in the following manner, to wit:
“He shall actually determine as nearly as practicable the true and fair value of each tract or lot of land listed for taxation and of each improvement located thereon and shall enter fifty percent of the value of such land and of the total value of such improvements, together with the total of such fifty percent valuations, opposite each description of property on his assessment list and tax roll. ...”
RCW 84.40.030, in so far as relevant to this action, provides:
*74“.. . . In assessing any tract or lot of real property, the value of the land, exclusive of improvements, shall be determined; also, the value of all improvements and structures thereon, and the aggregate value of the property, including all structures and other improvements, excluding the value of crops growing on cultivated lands and the growing stock of nurserymen. ...”
If the procedure prescribed in these provisions was followed by the county assessor, which we must assume to be the fact since there was no evidence to the contrary, then the improvement actually located on the west half of the quarter-quarter-quarter section was listed and assessed as an improvement on the east half, and this could have been done only on the assumption that the land on which it stood was. within the legal description of the east half. The plaintiff argues that the house could just as well have been assessed to the defendants as a severed improvement to the west half, since RCW 84.56.360 authorizes segregation of the improvements, from the land and separate payment of the tax. But the flaw in this argument is that the statute authorizes such segregation only where buildings, structures, or improvements are held in separate ownership from the fee. There has never been any claim of such separate ownership in this case.
On the face of the tax statements received by the defendants the improvements are listed as belonging to the east half, and there is nothing, in the record to support an inference that a segregation was intended.
RCW 84.64.180 provides, that a real property tax judgment shall be conclusive evidence of its regularity and validity in all collateral proceedings, except in cases where the tax has been paid, or the real property was not liable to the tax.
In Berry v. Pond, 33 Wn. (2d) 560, 206 P. (2d) 506, we held that, where taxes are paid under an inaccurate description of the land actually assessed, that fact may be shown as a defense to an action to quiet title brought by the holder of a tax deed describing the land so taxed. We stated:
*75“It is the fact of payment of the taxes on the land occupied, not the description used in the tax receipt, that is determinative of the issue here.”
The burden, of course, is upon the defendants to show that the taxes were actually paid. As the trial court observed in rendering its decision in this matter, the records of the assessor were in a state of some confusion, indicating that after the tax sale, the assessment on the house was transferred from the east half to the west half, and then, by way of “correction,” transferred back to the east half. In view of the fact that the land east of the county road had been improved and continuously occupied by the owners of the east half and regarded by all concerned as a part of the tract and that the house located west of the true boundary was nevertheless assessed by the county as a part of the east half, the trial court drew the only reasonable inference, that the assessor included the whole of the improved land in making his assessment.
By the express reservation contained in RCW 84.64.180, it was made manifest that it was not the intent of the legislature to subject land on which taxes have been paid to foreclosure, or to deprive one in possession of the right to set up his payment as a defense to an action to oust him. It is urged that the security of tax titles will be endangered if an error in description may be shown in establishing such a defense; but we see no valid reason why an error in description may not be shown to prove that payment was made, any less than other errors or acts of the county treasurer can be set up to show that a bona fide attempt to pay was made. That a tax deed may be invalidated on a showing that the owner made a bona fide attempt to pay his taxes and was prevented from doing so by the act of the county treasurer is well settled. Pierce County v. Newbegin, 27 Wn. (2d) 451, 178 P. (2d) 742; Nalley v. Hanson, 11 Wn. (2d) 76, 118 P. (2d) 435; Bullock v. Wallace, 47 Wash. 690, 92 Pac. 675. See, also, Comment, 23 Wash. L. Rev. 132.
It is true that the mistake was that of the defendants and their predecessors as well as the assessors, but it was *76an honest mistake, based upon a reasonable assumption, and, as we stated in Pierce County v. Newbegin, supra, “it is not the policy of the law that the owner should lose his land through excusable mistake.”
Upon the evidence, the court was justified in concluding that the defendants had sustained the burden of proving that the taxes on the disputed land had been paid.
The judgment is affirmed.
Mallery, Don worth, Finley, Ott, and Hunter, JJ., concur.