53 Pa. Stat. § 15047
Notices requiring compliance with this act shall be served upon the person required to make such compliance, or his agent, unless otherwise herein provided, by mailing a copy to the residence, if known, of such person or his agent; and, if unknown, by posting a copy in a conspicuous place upon the premises affected, which notice shall not be removed or defaced while the condition mentioned therein exists. All notices shall be complied with within such period, not exceeding thirty days, as the Bureau or Board of Health may determine; and, upon failure to comply, the Bureau or Board of Health may contract to have the necessary work done; and the cost thereof shall be made a lien against such property, and collectible as now provided by law: Provided, however, That if there shall be no funds at the disposal of such Bureau or Board of Health for the aforesaid purpose, then the Bureau or Board of Health may contract and have such work done, and the lien therefor shall be marked to the use of the contractor doing the work, and shall be collectible by such contractor as is now provided by law in similar cases: Provided further, That the owner of the property may, by permission of the Department of Public Health and Charities, pay the amount of the lien thereon in five equal yearly parts, with interest at the rate of five per cent.
53 P.S. § 15047