Of the 1,186 service stations inspected in 2011, four were found to be delivering short amounts and 21 had quality problems with the gasoline or diesel, according to the Authoridad Reguladora de Servicios Públicos.
This is the same agency that sets the prices of public services. Its quality control program involved laboratory testing of the fuel in the tanks of service stations. The work is done at the Universidad de Costa Rica.
The agency said that the results were better than in the past.
The short deliveries were from 240 to 310 milliliters per 20 liters of fuel. Involved were service stations in Buenos Aires de Puntarenas, Alajuela, Orotina and Cartago.
The quality problems included lower octane than specified or water and sediment in the service station tank, among other woes, said the agency.