I have a 4 plex each 2 bed one bath units, the septic tank leach bed is 30+ years old . I have had to have the tank drained every 3-5 months, I was told the leach bed is saturated and the only cure was replacement. the property is less than a 1/4 acre and replacement will cost $8,000 to $10,000 and the loss of parking spaces. This land is about 40 miles east of phoenix with an elevation of 1700 and low desert weather (7-9 inches of rain a year) Recommendations?