11-22-1999 Council Work Session - Laserfiche WebLink

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every existing on-site system by the trained City employee. Each system is physically inspected for proper operation, at least once every three years and more often if site or use parameters are more critical than normal. To date, after two summers of operation; this program has resulted m the inspeetion of some SOO sys tems ehosen on a priority basis. Inspcetion of the remaining (gcncfalty pmgHimmcd-fof completion during the summer of 1980; This inspection program has been in place for more than two decades, and has generated a substantial history for each individual system in Orono. A report is completed following each inspection. Each system is rated on its design and actual operating characteristics. The site is evaluated for limiting factors such as soil, slope, or groundwater and room for expansion or replacement, one copy of the report becomes a permanent City record, while the second copy is provided to the owner for his information. Most existing systems have been subject to soil borings in the past 4 years to confirm compliance with the required separation from zones of seasonal saturation. It is estimated that 42% of the approximately 1100 existing systems are non-compliant with the separation standards as of November 1999. and City ordinances require that systems be made compliant within specified time- frames when found to be non-comoliant. If repairs or alterations are required, the owner is notified and given a reasonable time to comply. Septic tanks are required to be pumped every three years or more often if there arc signs of trouble necessary based on inspection results. Pump reports are received from contractors and evaluated to assure compliance and/or to reveal premature signs of trouble. On-site system operation has proven reliable in rural Orono. Most of the ex isting sy stems were originally constructed or have been upgraded since the 1964- ordinance. System failures have been rare away from the lakeshorc. Most deftetenetes have been because of exee ssive water use or insufficient drainficid area for the typi cally heavy elay soils, of the 500 syste ms inspected in the last hvo yea rs, only 6 0 required repairs.'of those-only a handful! needed new septie tanks or drainficid, most requiring only miner tank repair or dramfic Id c.xpansionj Orono began to require the use of mound drainfield systems in the late 1970's in locations where soil were not suitable for trench systems, usually due to high seasonaltesting indicated conditions groundwater conditions. As of November 1999 approximately 37% of the existing on-site systems in Orono were mound systems. Of the approximately 700 systems which are not mounds, a majority are standard trench systems, of which approximately 2/3 have been identified as not meeting the minimum required vertical separation from seasonal saturation and which are on a finite schedule for replacement. Most of these nonconforming trench systems w ill be replaced bv mound systems. Orono has had substantial success with the use of mound systems, and the level of expertise of ISTS professionals has risen to a level over the last two decades such that mounds have become a reliable, standard sewage system and not the 'innovation' they were in the late I970's. Approximately 95% ot all new or replacement systems in Orono in the past decade have been mound systems. The education and inspection program is expected to increase awareness of proper septic system use and maintenance, and the required tank pumping will e.xtend usable drainfield life. In those c.xiatmg cases where groundwater is high, inno>'ativc shallow trench or mound type syatema have proven workable according to WPC-40 criterm: The majority of the developed properties on eld farmsteads I I 1 CMP 6-27