• Lien rights may be waived in a contract before performing any work.
• A subcontractor's rights are not waived by a clause in the prime contractor's agreement with the owner that states that any and all liens against the improvement will not be filed.
• A supplier does not waive a lien right by agreeing to arbitrate disputes, or by taking promissory notes as collateral security for the suppliers claim.
• Any waiver needs to be clearly made and will not be inferred through joint check agreement.
• "Paid if Paid" is enforced if explicit.
• "Pay when Paid" suggests time for payment.
• Language that appears only to set a time for payment will not be construed to establish a condition precedent for payment.

Retainage Provisions

Public

• Retainage may not exceed 5 percent of a progress payment, except when the charter of
  the contracting agency provides for retainage higher than 5 percent. As work progresses, a public agency may reduce or eliminate the amount of retainage after 50 percent of the work under the contract is complete, if in the contracting agency's opinion, such work is satisfactory. Elimination or reduction of retainage is permitted only upon written application by the contractor, which shall include written approval of the contractor's surety. However, when the contract work is 97.5 percent complete, the contracting agency may, without application by the contractor, reduce the retained amount to 100 percent of the value of the contract work not yet complete. OR. REV. STAT. §§ 279c.555, 560, 570.

Private

• Retainage may not exceed 5 percent of a progress payment. This provision is applicable
  to owners, contractors, and subcontractors. OR. REV. STAT. § 701.420. Securities may be
  substituted in lieu of retainage. OR. REV. STAT. § 701.430.