Sign the conditional one first

A lien waiver gives up some or all of your right to file a mechanics lien in exchange for payment. The part that bites AR teams is timing. Some waivers take effect only once the money clears. Others can be enforceable the moment you sign, check or no check.

Two questions decide which form you're holding. Conditional or unconditional: does it wait for payment, or not? Progress or final: does it cover work through a stated date, or the whole job? Put those together and you get the four standard forms that states with statutory waivers, like California, Texas and Nevada, prescribe.

The usual order is simple. Send the conditional waiver with the pay request. Release the unconditional one after funds actually clear. Don't count on a bounced payment giving your rights back. Nevada voids a waiver when the check or similar instrument fails to clear (NRS 108.2457(5)(e)), but that's Nevada, not a national rule. And a "final" label doesn't automatically release everything: California's final-payment forms preserve specified disputed extras.

Our full breakdown, with all four forms side by side: conditional vs. unconditional lien waivers.