ve been caused by difficult site conditions, review Table 3.4 to see if an alternative system is the best recourse. Installation problems can be either easy or impossible to fix. If you've got smeared trench sides, you're "outta luck." You can do a "root canal"-remov the pipe and gravel and dig out more dirt along the bottom and sides of the trenches (during dry weather), and then replace the gravel, filter layer, and pipe. If you've got a distribution problem, however, the solution is easier. Expose the distribution pipe in several areas, both where the sewage is surfac- ing and where there is no apparent problem, and check for places where the distribution pipe is too high. Scrape away some of the gravel from the high spots, lower the pipe, and replace the gravel, the barrier material and the soil cover. If you've got a sandy soil which has migrated into the gravel and left no room for sewage, you will have to remove the gravel and wash it. In order to prevent the same thing from happening again, lay filter cloth (geotechnical fabric) along the sides of the trench, replace the clean gravel and distribution pipe, then lap the loose edges of the filter cloth over the top of the gravel (see Figure 5.6). Open joint clay distribution pipe which has broken or crumbled is best replaced with Schedule 40 PVC perforated drain pipe. INFILTRATION PROBLEMS If the wastewater can't go down, you've got an infiltration prob- lem. The system is overloaded. This can be corrected, as mentioned earlier, in two ways: reduce the volume of water coming in or add more absorption capacity. The first step is to check all the water-using appliances for leaks, and fix them. Next, survey your family for excessive water use. Correct any overuse. Read the section on water conservation and implement any appropriate water use reduction techniques, includ- ing installing low-flush toilets and adding a grey water system. Check for and correct any siting and construction faults. If the foundation drain or downspout drains exit just above the drain