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Percolation Test

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  • 20-12-2009 11:31am
    #1
    Caoimhín
    Closed Accounts Posts: 3,789 ✭✭✭


    Hi lads,

    Is it a good or a bad thing if water just sits in a percolation test hole?


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    #2
    MINIDIGGER
    Closed Accounts Posts: 5 ✭MINIDIGGER


    I THINK ITS BAD I CAN FIND OUT IN WORK TOMORROW IF U WANT BU IM NEARLY SURE ITS BAD IVE DONE A FEW FOR BUILDERS IVE WORKED WITH


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    #3
    Caoimhín
    Closed Accounts Posts: 3,789 ✭✭✭Caoimhín


    MINIDIGGER wrote: »
    I CAN FIND OUT IN WORK TOMORROW IF U WANT
    I would appreciate that MINNIDIGGER.


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    #4
    MINIDIGGER
    Closed Accounts Posts: 5 ✭MINIDIGGER


    I NO THERE CAN BE A SLIGHT BIT OF WATER BU IF IT FILLS UP ITS NT GUD I DONT THINK ILL FIND OUT FOR CERTIN BU


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    #5
    BabyEater
    Registered Users Posts: 691 ✭✭✭BabyEater


    Have just had a percolation test done and was told the water should drop on average 100mm per 200 minutes.

    For this test a 4' x 4' x 18" hole was dug this had a 400mm deep hole dug in the center of it.

    This was filled with water with a measuring tape in the hole showing how far the water had dropped.

    I had 3 of the above holes dug.

    If the above test failed I think they would have repeated the test but without digging the 4' x 4' x 18" hole and just dig a 400mm deep hole and fill it up.
    As far as I know this would require a raised percolation area.

    My tester said that a bit of water would probably lie in the hole and if the council seen it would probably ask for further info.


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    #6
    Poor Uncle Tom
    Registered Users Posts: 14,547 ✭✭✭✭Poor Uncle Tom


    MINIDIGGER wrote: »
    I NO THERE CAN BE A SLIGHT BIT OF WATER BU IF IT FILLS UP ITS NT GUD I DONT THINK ILL FIND OUT FOR CERTIN BU
    Please save the TXT SPK for texts.
    BabyEater wrote: »
    Have just had a percolation test done and was told the water should drop on average 100mm per 200 minutes.

    For this test a 4' x 4' x 18" hole was dug this had a 400mm deep hole dug in the center of it.

    This was filled with water with a measuring tape in the hole showing how far the water had dropped.

    I had 3 of the above holes dug.

    If the above test failed I think they would have repeated the test but without digging the 4' x 4' x 18" hole and just dig a 400mm deep hole and fill it up.
    As far as I know this would require a raised percolation area.

    My tester said that a bit of water would probably lie in the hole and if the council seen it would probably ask for further info.
    These are very generalised statements as every test result will be different and the depth of the bottom of the test hole should be at the invert level of the percolstion trench intended for the site.

    Once the tests have been carried out the holes should be covered to prevent the ingress of rain water into the holes which could give an unfavourable impression of the soakage conditions.

    Generally, if there is water present in the percolation holes during inspection by the LA and if this differs from the information supplied within the site characterisation report, The council will either ask for the percolation tests to be carried out again when their engineer is present or they may refuse planning permission based on their site inspection.


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    #7
    No6
    Registered Users Posts: 2,489 ✭✭✭No6


    Caoimhín wrote: »
    Hi lads,

    Is it a good or a bad thing if water just sits in a percolation test hole?

    Is it in the trial hole the big deep one or the smaller percolation holes, if its in the big one then thats the water table level, if its high a raised percolation may be allowed to compensate, if its the smaller percolation holes (about 1ft x 1ft x 2 ft deep) then it means there is poor percolation at that level and most likely your T test will be a failure. There is an additional shallower test about 1 ft deep a P test which can also be done as there is often some movement in the topsoils whereas the subsoils can be like a soild sheet. If you get a reasonable P test then you may be allowed a raised percolation area with a treatment unit but I would get the test results first and if they are poor talk to you co council before you proceed and spend a lot of money on fees as if you havn't got satisfactory percolation you will be refused. You couls alternatively dig another trial hole and test elosewhere in the site or find an different site. You architect or engineer should be telling you all this!!!


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    #8
    liamolaighin
    Registered Users Posts: 160 ✭✭liamolaighin


    Oh its great if you are thinking of going with a swimming pool in your build. No need for a water barrier that way to keep the water in your pool! ps....are u serious??? What do you think a 'percolation' test is actually for...
    Caoimhín wrote: »
    Hi lads,

    Is it a good or a bad thing if water just sits in a percolation test hole?


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    #9
    Caoimhín
    Closed Accounts Posts: 3,789 ✭✭✭Caoimhín


    liamolaighin wrote: »
    ps....are u serious??? What do you think a 'percolation' test is actually for...

    Yes I am serious, I understood it was something to do with the water table or septic tanks.


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    #10
    Poor Uncle Tom
    Registered Users Posts: 14,547 ✭✭✭✭Poor Uncle Tom


    liamolaighin wrote: »
    ....are u serious??? What do you think a 'percolation' test is actually for...
    No call for that...
    Caoimhín wrote: »
    Yes I am serious, I understood it was something to do with the water table or septic tanks.
    There are two seperate tests which are carried out on a site, a watertable test and a percolation test.

    The watertable test will find out if the watertable in the area is within 2.2m of the ground level and if it is then what level it is at. It is not considered a fail if there is a seperation distance of 1.2m between the watertable level and the bottom of the percolation trenches.

    The percolation tests will determine the quality and speed of soakage the ground has in order that a percolation area can be designed and recommended for the site. The structure of the soil, surrounding features, bedrock level as well as the watertable level all play a part in the design of the sewerage treatment system as a whole, ie., septic tank, bio unit, percolation area, raised bed, reed system, etc.


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