The practical difference is payment risk. A conditional lien waiver is usually tied to payment actually being received or clearing. An unconditional lien waiver can give up rights even if the contractor has not truly been paid, depending on the jurisdiction and document language.
Contractor rule of thumb
- Use conditional progress waivers when payment is pending.
- Use unconditional progress waivers only after the matching payment clears.
- Check open change orders, retainage, and extras before final waiver paperwork.
- Keep the waiver connected to invoice number, payment amount, and payment date.