This is an appeal from the dismissal of a complaint filed under the Oregon tort claims act, ORS 30.260 to 30.300, against the city of Hillsboro. Plaintiffs, owners of residential property, allege that they purchased their property relying upon defendant’s representation that the abutting street would be developed as a city street, that defendant’s intentional and negligent failure to enforce city ordinances resulted in the developer constructing a substandard street, and that they were damaged in the amount of $38,627.90.
The court heard the matter as a motion for summary judgment upon the following stipulated facts:
(a) City ordinances empower defendant to "permit any * * * developer to construct any street * * * subject to [certain] terms and conditions” which include city approval of design and specifications, issuance of a permit, and inspection.
(b) The developer’s construction of the street commenced in October 1971 and terminated in September 1972.
(c) On September 19, 1972, defendant took initial action to form an improvement district and on November 8, 1972 adopted an ordinance authorizing improvement of the street. Sometime between these dates, a public hearing was held.
(d) Defendant completed improvement of the street on September 26, 1973.
(e) On November 6, 1973 defendant adopted a resolution of intent to apportion the costs of the improvement. On November 7, 1973 defendant adopted an ordinance authorizing the improvement. Public hearings were held on December 4, 1973 and January 2, 1974 and on January 2, 1974 defendant adopted an ordinance declaring an assessment in the amount of $38,627.90.
(f) On February 8,1974 plaintiffs gave notice to defendant of their claim.
(g) On April 25,1974 plaintiffs filed this action.
*164Defendant alleged several affirmative defenses including failure to give timely notice as required by ORS 30.275(1). We do not need to consider the other defenses because of our decision on this issue.
The statute requires that:
"(1) Every person who claims damages from a public body for or on account of any loss or injury within the scope of ORS 30.260 to 30.300 shall cause to be presented to the public body within 180 days after the alleged loss or injury a written notice stating the time, place and circumstances thereof, and the amount of compensation or other relief demanded.
‡ * * *
"(3) No action shall be maintained unless such notice has been given and unless the action is commenced within two years after the date of such accident or occurrence.” (Emphasis supplied.)
Read together, subsections (1) and (3) indicate that both the 180 day notice period and the two year statute of limitations run from the same date. We construe the statute to incorporate general common law and statutory principles for determining the accrual of a cause of action.
A cause of action usually does not accrue until there has been a tortious act and injury or damage. The two elements may be contemporaneous or there may be a time lapse. Nonetheless, the action cannot accrue until both have occurred. U. S. Nat’l Bank v. Davies, 274 Or 663, 548 P2d 966 (1976). A corollary rule applicable in malpractice actions is that in order for the cause of action to accrue there must not only be a tortious act and injury, but also a reasonable opportunity for discovery. U. S. Natl Bank v. Davies, supra. The policy considerations embodied in the malpratice rule arguably are applicable to the allegations in this case. The alleged defects in the construction of the street might not be readily apparent and thus plaintiff should be afforded a reasonable opportunity for discovery. We do not here decide that issue because even under the most *165liberal rule plaintiffs’ cause of action accrued more than 180 days before notice was given.
Plaintiffs rest their entire case on the contention that the injury was the assessment on their property and that did not occur until January 2, 1974. To the contrary, the injury to plaintiffs as landowners presumably was the diminution in the value of their property caused by the alleged defective construction. The actions taken by defendant to correct the defects are wholly fortuitous. Defendant could have elected not to improve the street, or to improve the street and impose a general tax on all taxpayers, or to sue the developer, or impose an assessment. The amount of the assessment might have been relevant evidence in determining damages, i.e., diminution in value, but certainly is not the legal measure of damages as contended by plaintiffs. See City of Portland v. Kamm, 10 Or 383 (1882). Similarly, subsequent sales by adjoining property owners would be evidence in determining damages. But obviously such sales would not be considered an integral element of the cause of action.
The fatal flaw of plaintiffs’ contention that the injury was the assessment is that if this is the case, then defendant is immune from liability. ORS 30.265 provides:
"(2) Every public body is immune from liability for:
* * * *
"(c) Any claim in connection with the assessment and collection of taxes.”
Plaintiff contends that what is at issue is an assessment and not a tax. Courts have on occasion recognized such a distinction for determining whether particular assessments are subject to certain constitutional restrictions. See King v. City of Portland, 2 Or 146 (1865). However, even such cases acknowledge that an assessment is a tax in the broad sense that it constitutes an exercise of the sovereign power to tax. King v. City of Portland, supra at 153. In Colby v. City *166of Medford, 85 Or 485, 525, 167 P 487 (1917) the court stated:
"* * * [I]t must be remembered that although a special benefit assessment is to be differentiated from a pure tax, nevertheless the power to assess is embraced in and its exercise is a manifestation of the power of taxation * * *
We construe ORS 30.265 to encompass any manifestation of the power of taxation. Whenever government taxes, whether by general levy or special assessment, the result is inevitably fractious. The legislature intended that public bodies and officials have broad immunity in exercising their taxing powers.
Plaintiff also contends that the injury was not discovered until the assessment. In the fall of 1972 defendant announced the formation of the improvement district and held a public hearing to discuss the needed improvements. Under the allegations of plaintiffs’ complaint, we must presume that the purpose of the improvements was to correct the alleged construction deficiencies. Defendant’s action and the public hearing as a matter of law provided plaintiffs a reasonable opportunity for discovery.
Affirmed.