An irrigation specialty contractor is a contractor whose contracting business consists of the execution of contracts requiring the experience, financial means, knowledge, and skill to install, maintain, repair, alter, extend, manage, monitor, audit, or, if not prohibited by law, design irrigation systems. An irrigation specialty contractor may install, maintain, repair, alter, extend, manage, monitor, audit, or, if not prohibited by law, design irrigation systems, including any excavation work incidental thereto. An irrigation system includes all: piping; fittings; sprinklers; drip irrigation products; valves; irrigation controllers; control wiring; rain sensors; water pumps; water conservation devices; water harvesting systems; irrigation main lines downstream of a utility potable water meter or utility alternative water supply distribution line and dedicated backflow prevention device; and associated components installed for the delivery and application of water for the purpose of irrigation. Nothing in this rule shall be deemed to restrict or limit in any manner the scope of work authorized by law of other contractor classifications.