The City of San Diego provides you with direct access to bidding and contracting opportunities on all its construction projects. Learn how the County buys products and services.Search contracts, find open solicitations on BuyNet. Register with BuyNet today and begin receiving notice of business opportunities from the County of San Diego. Applications can be submitted at any time; however, the annual validity of the District's Informal Bidding Contractors List extends until December 31st. Submit Bids –All bids must be submitted electronically via PlanetBids and are typically due at pm.