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+--- Thread: Catchment tank filter question (/showthread.php?tid=12750)
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Catchment tank filter question - redefinehappy - 11-26-2013
Hi everyone - I have a question about filters on catchment tanks. Are they necessary if you are not using the tank for drinking? I have checked through the forums/archives to see if this has been addressed previously, but couldn't find anything.
Backstory: We purchased our (newly built) house a couple of months ago. Final inspections were done August of this year. The builder (private individual)had installed the following:
3,400 gallon tank
food grade liner
1st flush diverter with a drain hole and removable end for cleaning
sock at the end of the drain before hitting the tank
well fitted tank cover
ball perched on cross-strings below the cover and above the water to prevent the cover from sinking/hitting the water
water is taken in from the tank via a floating tube in the middle of the tank (ie, from the top of the water not middle or bottom, so no real sediment issues)
no standing water in any pipes
normal pump into the house
We put 5 oz of chlorine per 1k gallon into the tank weekly when it's raining a lot, bi-weekly when it's a bit drier. We also check the gutters, sock and diverter weekly to get rid of any leaf, etc build up. The water is clear and we use it for showering, washing dishes, watering plants, etc.
BUT, there is no filter at all on the system. Sediment catching or otherwise. Is this a safe system or do we need to install at least a simple filter?
Any advice and/or suggestions would be appreciated!
I may not have gone where I intended to go, but I think I have ended up where I intended to be.
~Douglas Adams
RE: Catchment tank filter question - seekir - 11-26-2013
Seems like your system has many good features that remove or minimize sediment and hygiene problems. I'm not a plumber, but some shower heads, valves (including toilet valves and mechanisms) may benefit from the filtering I guess you're trying to avoid. The filters add to the cost/nuisance of catchment systems, but I think most of us use them.
RE: Catchment tank filter question - terracore - 11-27-2013
There are differing levels of paranoia regarding what's in the catchment water. You can have the fanciest diversion system in the world but when a bird or rat craps on your roof at the right time it's going into your catchment tank. Roof rat proof? Well, the wind will blow sediment onto your roof that a rat has crapped on. We ALL have crap and piss in our water. ALL WATER HAS BEEN CRAPPED AND PISSED IN. Even in a pretentious looking bottle with a foreign sounding name and a fancy label. Your catchment tank is just a big water bottle. You can either filter it like the bottled stuff or not. But enough about that.
I'm assuming that you are bathing in this water. Some people believe that parasites or microbes can migrate from your catchment water through microscopic abrasions in your skin and may cause an infection that can kill you within 72 hours. They are probably right that it's possible.
But why not make your catchment water better than that pretentious stuff? Add a few filters and a UV sterilization or reverse osmosis system and your catchment water will be good enough to bottle and sell to people in Manhattan for $12 a bottle. You can bathe in it, make ice, drink it, brush your teeth, and do all those other things that people like to do with fancy water.
The only real "whole house" solution is a UV system. It works best when the water is filtered to 5 microns. Usually there is a sediment filter of 20 microns followed by a 5 micron filter, which is then sterilized by UV energy. This will keep exotic parasites from attacking you when brushing your teeth or showering. Another option is to put a reverse osmosis filter only on one spigot where the drinking water is obtained. Reverse osmosis is a great filter technology but it is energy and time consuming and takes time to create and store filtered water for drinking, so you can't bathe in it. UV systems are "on demand" and can filter/sterilize water as fast as you need it.
Another option, is that some people have been bathing in and drinking catchment water for decades with no ill effects. Even with all the bird and rodent feces and urine in it.
RE: Catchment tank filter question - MarkP - 11-28-2013
As a reality check, however dirty it actually is, the water in your catchment system, having come straight from the sky onto a relatively clean roof with no foot traffic, is way, way cleaner than the hot ponds. Ironic that people should swim in them then balk at showering in catchment water.
RE: Catchment tank filter question - VancouverIslander - 11-28-2013
While MarkP is correct, I'd still install a filter if just used for wash water and a filter AND a UV system for drinking water.
RE: Catchment tank filter question - terracore - 11-28-2013
In my previous post I completely missed the part about adding chlorine. I've never considered treating my catchment tank like a public pool. Depending on where you are and the size of your roof, your catchment tank may be harvesting over 200,000 gallons of water a year, even if most of that is dumped out the overflow pipe. Other than stringent testing after every rain, and daily during a drought, I can't imagine how adding chlorine to your catchment tank is beneficial and it might even be harmful to your liner or cause it to leach out chemicals. You're either dumping in chlorine that will soon be flushed out, or dumping in chlorine that will become inert before the next rain, either way it seems like a waste of time/money. I've only heard of using chlorine for flushing out the pipes inside the house after a sterilization unit has been replaced or something. If it were me I would take the money that you are currently spending on chlorine and use it instead replacing filters ever month or two. Personally, I like going to my refrigerator and having it eject filtered, chlorine free, sterilized catchment ice and water from the door unit into my glass and drinking it on a hot day.
RE: Catchment tank filter question - MarkP - 11-28-2013
I'm not saying it is the right way to go but I shower and brush my teeth with water straight from the tank. I use the catchment water (boiled) for tea. I agree I ought to at least get sediment filters in place. There are some things they will catch. My energy budget does not currently allow UV sterilization.
RE: Catchment tank filter question - hotinhawaii - 11-29-2013
You would do well to at least install a 20 micron sediment filter. The openings in some faucets are so small that very small grains of debris will clog them up over time.
RE: Catchment tank filter question - bluesboy - 11-29-2013
Sounds like you've taken precaution for everything you can see. The 5 and 20 micron filters are for what you can't see. I'd advise you to get them. We just got 2 good quality housings, mounting brackets and filters for $250 from waterworks in hilo
RE: Catchment tank filter question - MarkP - 11-29-2013
Can the filters be installed before the pump?