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If
you are located in a test drill area, soils
testing of some type will be required. Test drills are arranged through Water
Protection by appointment only, at least 24 hours in advance.
These appointments require the presence of Water Protection staff. A drilling
rig capable of drilling a 40-50 feet hole that is at least 1 ˝ feet in diameter
must be used for this test.
The
test hole is usually drilled by the septic system contractor who is hired to
install the system. A test hole can often be used as part of the septic system
if a 3 foot diameter hole is dug for the test drill.
Test
drills are sometimes conducted with a back-hoe in areas where high water tables
prevent the use of typical seepage pits. Other types of septic systems may
need to be designed in areas such as this.
A
test drill may be waived if test drills on adjacent parcels provide
adequate knowledge of soils in the vicinity of your parcel.
Test
drills do not always provide enough information about the soil to allow Water
Protection staff to design the system. (The success rate of test drills is
approximately 90 per cent). In the event the test drill fails, further testing
must be conducted by private engineering firms.
These firms employ registered professionals who are enabled by law to perform soils
testing and prepare design reports for review by this department. Those
professionals are:
If
testing of this type is required, it can dramatically increase the total cost
of the septic system installation. If your parcel is located in the Sacramento River Delta or the Garden Highway area, you must speak to Water
Protection staff (916-875-8400) to determine the type of testing required.
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