The question is almost always asked in the wrong shape. It is not how long an aviz is valid for, but until what event. The Cod answers the second, and only that explains why some avize have to be redone and others do not.
The rule
Article 311 paragraph (1) says that avize and acorduri issued, requested through the certificat de urbanism, including at the feasibility-study stage or that of the documentation for authorising intervention works, keep their validity until the recepție at the completion of the works.
The text attaches the condition immediately: provided no new elements arise and the conditions underlying their issue do not change. For the technical solutions at the stage of the technical documentation for authorisation, the marker runs to the completion of the corresponding works, respectively to the signing of the final acceptance report.
So the marker is not the calendar. It is the stage of the works, plus the stability of what you had approved.
Note what the article does NOT say: the calendar stays in the neighbouring articles. The permit itself has a 3-year term from issue, extended over the execution period once you notify the start of works (article 309), and lapses on non-start or on non-completion within the execution period (article 310). Article 311 says only that avize requested through the certificat de urbanism have no calendar term of their own, not that your dossier has none. Other avize do: the aviz unic integrat obtained at the PUZ stage lasts until the permit is issued (article 249 paragraph (4)).
What breaks the validity
Paragraph (3) is short and is the operative part: paragraph (1) does not apply where modifications arise that require the avizare procedure to be restarted.
The wording is worth reading twice, because it does not say any modification. It says the modifications that require the avizare to be restarted. An aviz does not lapse because a year has passed over it, but because the approved project has changed, or the conditions it was issued on have.
The cost consequence is direct and appears nowhere as a separate fee. You do not pay for the passage of time. You pay for changing the solution, and the bill arrives as a procedure restarted at every issuer the change touches.
The two regimes that fall outside the pattern
Paragraph (2) covers special telecommunications infrastructure: the permits, certificates of urbanism, avize, acorduri and avize de amplasament keep their validity throughout implementation, until the final acceptance report is signed, on condition that execution begins within 36 months of the permit being issued.
Paragraph (4) does the same for national-interest transport infrastructure projects, without the 36-month condition.
These are large-project exceptions. If your dossier is a house, or an intervention on one, paragraphs (1) and (3) are all that concern you.
What this changes in practice
The order of work inverts. Under a fixed term, the hurry was to file before something expired. Under article 311, the hurry is not to touch the solution once you hold the avize, and if you must touch it, to know in advance which issuers restart.
The list of avize your dossier needs comes from the certificat de urbanism, explained on the page about avize for the building permit.
What to watch
Article 311 paragraph (3) does not say which modifications require the avizare to restart. In practice each issuer draws that line, and until the norms fix it you will learn the answer by asking before you change the solution, not after. The deadlines you are answered within are in what the aviz issuer owes you.
This article is analysis, not legal advice. Provisions are cited from Legea 169/2026, published in Monitorul Oficial no. 661 of 10 August 2026. Check your own situation with the issuing authority. Romanian legal terms are kept in the original, because the Romanian text is the one that governs.