Who’s writing this stuff ?

Dave graduated from the University of Washington in 2006 with a degree in environmental science. He has 42 years of experience in the “workplace”, including overseas service in the U.S. Navy in the late 1960’s.  He has worked as a mathematics instructor, an electronics technician, and an antique clock repair technician. Dave has spent the past 7 years designing, studying, building and testing slow sand water filters.

Dave T

A little older now. . . .


9 Responses to Who’s writing this stuff ?

  1. Ersan says:

    Hi Dave. Thank you for this great blog, really informative one.

    I have an hydroponic setup and i am building a quartz sand filter.
    But i have a question if you have time.
    Do you think this filter will also keep the nutrients beside the harmful bacterias?
    If so, there will be a problem for me :)

    Thanks in advance.

  2. Wendy Woodruff says:

    I recently saw a picture on a Facebook group of Free and Equal that stats that it is banned to collect rainwater in the USA. I find their picture very misleading, as I know it isn’t banned in the entire USA, but I can’t find anywhere to see just how many states it is actually illegal to do so. Can you tell me exactly how many states it is illegal to do so?

  3. Pablo says:

    Dear Dave,

    I would like to use the slow sand filters you described in a research project that aims to provide drinking water to small groups of people in rural areas in Argentina. However, you mentioned that you cannot recommend it as a dependable method of producing potable water.

    What does the slow sand filter you present need to be able to produce potable water?

    I am looking forward to hearing from you soon,


    • filter_guy says:

      To determine if a small slow sand filter will provide potable water, the filter would need to be set up and a pilot test done. This means the filter would need to be set up at the location where it will be running, using the same water all the time; and then be tested by a qualified knowledgeable person in the worst of conditions and the best of conditions. Also the input water would need to be tested to determine the extent of contamination. Then the owner / operator would need to be trained on how to properly use and maintain the filter. Output can vary considerably, and it is possible for a slow sand filter to produce water that is not completely purified if it is not maintained correctly. Also contamination can come from anywhere. And anything can be in water – anything. A UV filter may be needed in some cases. Be advised that the filters we have here are not the same thing as a “Biosand filter”.

      We have 12 filters running here, and I’m not sure which one you are referring to. Four of the filters purify roof water, and 2 of them purify shallow well water. These are the ones that have been tested by EPA certified laboratories. The filters work, most of the time, at this location here in the northwestern part of Washington state, with the water sources we use here: roof water, and shallow well water. The output varies considerably depending on the condition of the input water, which also varies considerably. There is no guarantee that the filters we describe here will work to provide potable water anywhere else 100 percent of the time. Without proper testing at the place of operation, there is no way to be certain of the output purity. Also, be advised that the owner / operator of any slow sand filter is totally responsible for its operation, and totally responsible for assuring proper maintenance and testing.

  4. filter_guy says:

    Actually, some people can legally harvest rain water in Colorado. My humble apologies if I give the impression that rain water harvesting is illegal in Colorado for every one. It is for some people, and for others, it is ok. The link in this post goes directly to the Colorado gov’t website with an explanation there.

  5. Cassia says:

    Thank you for doing all of this research. Saved me a whole lot of time. ( :
    I happen to live in Colorado and was curious about our water regulations because just last year Costco was selling rainwater collecting barrels. I am all about sustainable living and was wanting to use one for watering my garden. Sad to hear that it is completely illegal and highly regulated. I am curious as to why, of all places, Colorado has regulations on rain water collection. Our area depends on snow melt, reservoirs and wells for our water reserves; I don’t see how collecting rain waiter would adversely affect our environment. Just another reason why I’m heading to Wyoming!

  6. filter_guy says:

    Thank you for the input, Claver; your questions bring up some important points.

    The filters here are not being used to provide potable water; and unfortunately, we cannot recommend them as a dependable method of producing potable water. The site http://www.biosandfilter.org/biosandfilter/ is the best source of information on biological sand filters that may be used for supplying potable water in areas other than the the northwest part of the north american continent. The people who run that website, biosandfilter.org, have tested filters in other parts of the world successfully for a long time (they have already done “pilot tests”), and have far better information that we do regarding that matter.

    The filters we have here do provide water that is clean enough, and safe enough to use on a vegetable garden; and these filters do significantly improve the quality of the water that runs through them. The filters will provide water that can be used for anything but direct consumption on a regular basis. Further disinfection and filtering is still needed on the output of these filters in order to make the water potable on a regular dependable schedule of use.

  7. Claver Nitereka says:

    Hello Dave,

    I just came across of your excellent work , I sincerely thank you for sharing it. This is going to help lot of people in non developed countries where most of people(including my parents) , living in rural areas, are still drink contaminated river water. Diseases and death toll are very high in these areas, by example in Burundi where I originally come from.

    I have been, since this Christmas, researching on roof rainwater harvesting techniques to supply potable water and using Bio-sand techniques for filtering. Another area I am researching is the DIY solar panel in order to use it in conjunction.

    As I am new in the area , I would appreciate your mentorship to conduct this project.
    Is it possible to visit or talk to you and review your systems closely if you are close to my location. I am an aerospace engineer and live in Snohomish?

    My short term goal is to provide potable water to my parents and their neighbors by April 2014.
    The project is divided in 3 steps:
    1. Roof Rainwater catchment. Installing gutter on the roof will done in February 2014.
    2. I identified a 1000 gallon barrel for water storage.
    3. Filtering, treating rainwater to make it drinking water. This is the phase I need the help and guidance. A good news is that rural areas do not have chemicals, they do not use pesticide. Most of problems are from fecal and other waste.

    I appreciate any support that can help people.

    Thank you very much again.
    Have a nice day

    Claver Nitereka