ISDS 



SYSTEM FAILURE AND REPAIR 



Although ISDS systems properly sited, installed and maintained can provide effective 

 waste disposal, many factors can contribute to system failure, as outlined in other sections. 

 To summarize, causes for failure include: 



• inadequate sizing; 



• siting in substrate unsuited to installation of ISDS systems; 



• use of tanks and D-boxes which are not water-tight; 



• faulty installation; insufficient attention to the future integrity and performance of 

 system components; 



• insufficient maintenance; 



• use of septic tank cleaners; and 



• inadequate/Improper repair 



In many areas of the Bay watershed, and elsewhere in Rhode Island, particularly in the 

 Salt Pond watershed, ISDS failure has led to closure of shellfish beds, contamination of 

 groundwater by nutrients, pathogens, and organic chemicals, and system overflows 

 creating a serious threat to public health. The situation is particularly acute where dense 

 concentrations of systems are located in old neighborhoods on substandard lots and where 

 old inadequate systems designed to support seasonal use are now being reUed upon to 

 serve dwellings converted for year-round use. Frequentiy, the most dense concentrations 

 of these old grandfathered systems are pn soils least suited to use of ISDS as a waste 

 disposal alternative. 



A key weakness of the enforcement program is the fact that enforcement 

 action can be taken only when a system has already failed, while a 

 definition of "failure" is not specified in the regulatory language. Further, 

 current ISDS regulations provide no criteria for maintenance or repair, 

 although pumping is recommended every three years. The vague regulatory 

 language lessens the ability of the DEM legal staff to efficiently issue 

 administrative penalties, and serves to complicate the effective targeting of 

 Sewer and Water Failure Funds. 



Recommendation to RIDEM 



***Establish a detailed definition of system failure based both on design 

 and performance criteria: 



Design criteria should address: 



• hydrauhc failure; 



• failure of the designed system to meet projected flow needs; 



• failure of the designed system to properly consider site factors affecting system 

 function; and 



• failure as defined structurally : (a) contact between groundwater and bottom of 

 system and/or (b) effluent entering the water table without reasonable technical 

 potential for adequate treatment through unsaturated soil. 



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