Err3700 R20 Water Softener Price . It is highly recommended for either municipal or well water supplies. Other threads here about ecowater mentioned paying around $3000 without any sort of discount. Holmes Ecowater How Much Does It Cost to Operate a Water Softener? from holmesecowater.blogspot.co.uk You have converted 3700 errorcoin to euro. Continuous operation at flow rates greater than the certified flow rate 35 a 447/8 b 341/4 c 3 1/2 1intermittent flow rate does not represent the maximum service flow rate used for determining the refiner’s rated capacity and efficiency.