Category Archives: slow sand water filter study and construction

How to know if a slow sand filter I see on the web will actually work when I build it

There are more and more websites and YouTube videos appearing on the internet showing how to “build your own slow sand filter”. Some of the videos have what appear to be very impressive results; but be cautious. The correct functioning of … Continue reading

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Slow sand filters in below freezing weather

The temps have been 28 degrees F at night for the past 4 days now. All the filters have frozen up at night, and thawed out during the day. Last night, Jan 2/3 was the coldest so far, 25 degrees … Continue reading

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Rainwater harvesting in Washington state

Slow sand filters are totally sustainable, will work on gravity feed only, take out hydrocarbons, bacteria, viruses, and do not require addeed chemicals to operate. Check out the websites below. And check out the post just before this one if … Continue reading

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Slow sand filter field test (filter 5)

Filter 5, the most recent filter set up here in May of this year is now working.  The drainpipes inside the filter at the bottom of the barrel are covered by 4 inches of pea gravel. The sand directly on … Continue reading

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slow sand filter construction techniques

This is yet another update on what has been learned regarding the construction and operation of a small slow sand water filter. These are issues that stand out after experience building, testing, and operating small slow sand filters over the … Continue reading

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Testing the water from a slow sand filter

Some of the water quality tests done here on filter 4 and 5 are done. These tests were done with the testing kits available from Micrology Labs. The interpretation of the results of our tests are posted here along with … Continue reading

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Roof water filtration system

More notes on roof water quality required for a slow sand filter: Experience here in the art of roof water harvesting and slow sand water filter construction is a continual learning experience. The newest roof water filter here (filter 5 … Continue reading

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Finding sand and mesh size for a slow sand filter

This is an update of the previous post on slow sand filter sand sources. Instead of trying to find specialized sand sizes from a manufacturer, it can be more convenient to sift easily available sand to get the right grain … Continue reading

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Slow sand water filter sand source

A SUMMARY OF THIS POST: For a slow sand filter to work we need to use “uniformly graded” sand. “Uniformly Graded” sand means sand that has already been processed (sifted) so that the grains of sand it contains are mostly … Continue reading

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water filter sand

This is an update on the post about sifting sand for a slow sand water filter. I wrote about this in response to a question from a reader.  I recommended using stainless steel wire cloth to sift “play sand” so … Continue reading

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