New California legislation changes the minimum requirements for mechanics liens to be obtained by contractors and other providers of goods and services to real estate, such as construction projects and tenant improvement work. Specifically, a new form of Notice of Mechanics Lien, and copy of the intended lien, must be duly served on the property owner in advance of recording a mechanics lien. Then when an actual mechanics lien is to be recorded, it must be accompanied by an affidavit of proof of service of the advance Notice. The new law (adopted as state bill AB457) does not change the substantive requirements of mechanics liens, but will change the casual use of mechanics liens by contractors and vendors which did not do their homework in advance to ripen mechanics liens rights. Failure to follow the more rigorous new procedures will render a mechanics lien unenforceable as a matter of law, so property owners now have an additional basis to test any mechanics lien recorded after January 1, 2011.