Business and Professions Code § 7167

(a) Any contract, the primary purpose of which is the construction of a swimming pool, that does not substantially comply with paragraph (4) or (5) of subdivision (c) or paragraph (7), (8), or (9) of subdivision (d) of Section 7159, shall be void and unenforceable by the contractor as contrary to public policy.

(b) Failure by the contractor to comply with paragraph (5) of subdivision (c) of Section 7159 as set forth in subdivision (a) of this section does not preclude the recovery of compensation for work performed based on quasi-contract, quantum meruit, restitution, or other similar legal or equitable remedies designed to prevent unjust enrichment.