San Diego County’s cash-strapped water authority is considering a plan that could remove a discount it gives to local farmers — something farmers claim could put them out of business. The authority gives a roughly 25% discount to about 1,000 farmers, who grow everything from flowers to avocados. Critics say removing the discount is shortsighted because it threatens to kill off a customer class the water authority can’t afford to lose. At the same time, rates for other customers may increase to cover the authority’s costs.