My home on STX is about 4 years old right now. After years of planning, we finally made the big move down and are now full-time residents.
It had been six months since our last visit, so I changed out my 3 water filters (2 partical and a carbon filter) and cleaned off the UV light filter bulb and added about 2 cups of bleach to the 12,000 gallon tank. We drank bottled water for a few days after that and then began drinking the filtered water from the cistern. Ive got to say, the water that we run through this system always tasted great.
The cistern was full, with all the recent rain, and the other evening I saw eyes in one of the overflow pipes. It was a frog. I removed the screen and he jumped right out. Of course that inspired me to pull the cover on the cistern and take a better look in there. There is some minor sediment at the bottom, but nothing swimming about or climbing along the walls. Today I decided to give the gutters a good cleaning. One of the metal mesh covers over one of the gutter down spouts was half off. I figured that must have been where Mr. Frog got in, except 2 other downspouts on the other side of the house each had a frog in them as well. Healthy frogs, but how did they get in there and where are they living? In the piping between the gutters and the water in the Cistern?
I just went out tonight to take another glance at the overflow pipe, and it looked like a salamander/lizard was staring back at me. I pulled the screen cover off hoping he'd hop out as well, but he ran back into the cistern. I pulled the cover in the house again and looked all around inside the cistern, and nothing.
So what's the deal here. Do I have a major issue of some kind, or is this normal?
Been here 5 years.
Same frogs and others critters in my cistern as you have.
My remedy was to add filters, both sediment and UV, restrict critters from the overflows with plastic caps with hole drilled them and last but not least we added leaf harvester system, which pre-filters out most of the accumulation of gook that comes from your roof.
We drink our water w/o treatment with sanitizers.
I like the rain harvester, however I don't think there's enough room on my downpipes to install something this big. I spoke to an employee over at Galliws Bay Hardware about the galvanized screens that get placed inside the top of the down spouts (on top of the gutter itself) and asked if plastic ones were available instead. The galvanized ones I have seem to rot out after about 2 years. He said that plastic ones were available and they would be ordering them and getting them in soon. Island -time soon I'm sure 😉
Cleaning requires emptying cistern so best to do when low on water.
If you're going to clean it, best to reseal it at same time. That way, it's done.
Some companies offer a water tank for water use during this period or you might plan on a mini vacation as the process generally takes a few days to clean, reseal and cure before putting water back in. During this period, you won't have water.
Frogs in cistern are common but they do eat mosquitoes.
I have screens on all overflow pipes and I use the galvanized downspout covers which do have to be replaced every couple of years.
I insert them so that the open end is down and the closed end pops up out of pipe entrance as if base is in downspout, you still collect leaves and requires cleaning
May as well clean and recoat your roof before cleaning the cistern.
If you have a neighbor close enough, you can run a hose to their cistern so water isn't wasted since cistern has to be emptied.
Best to cut back or trim any and all overhanging trees and branches from your roof.
It just amazes me that any frogs got in the system in the first place. I've got no overhanging trees and it's a pretty dry environment out here. Im at about 200' above sea level on a hillsude as well, not down in the wetter valley.
I did notice how well they climbed walls though.
Thanks for all the input.
Hopefully I can hold off on a full cleaning for another year.
Frogs like to hide out during the day in a moist, dark environment so a cistern is perfect. They have to come out at night since there is hopefully little for them to eat inside a cistern. If you keep your cistern chlorinated by adding 6 ounces of regular unscented bleach per 1000 gallons of water currently in the cistern then frogs will not live in the cistern as they are very sensitive to bleach. Chlorine will kill mosquito larvae that hatch in your cistern as well. The screens are needed on your cistern overflow pipes to keep rats from climbing into the pipe, falling into your cistern, and drowning. Don't use a fine screen for this as it significantly reduces the available surface area in the event your cistern overflow is actually needed. Mosquitoes lay eggs in the gutters and the larvae are flushed into the cistern when it rains. They don't fly into the cistern to lay eggs, contrary to popular opinion. Gutter downspout screens are good to keep leaves and other organic material out of the cistern but have to be frequently cleaned or they plug up the downspout. Rats will often seek moisture when poisoned and can end up dying in your gutters, where there is often a little standing water. Then as they decay the rainwater will flush their remains into your cistern, which is another reason to chlorinate your cistern.
I've never really had an accurate measurement of bleach per 1000 gallons of water. I'll remember that.
Everyone seems to have their own bleach mix ratio around here (like cocktail / rum ratios). I was told about 2 cups should be good for my size cistern. I'll have to add a little More tomorrow.
I haven't cleaned my cistern ever and probably never will unless the sediment accumulates as high as the intake pipe. I've seen the odd frog or gecko in there from time to time but never worry about them. I pour a few chugs of bleach in every few months. The water has always been just fine and tested well.
We recently installed a triple carbon filter system with properly sized, high quality UV sanitizer (not the crap from the hardware store). The water is still very nice and I feel a bit better with the higher level of sanitation because we have an AirBNB unit that is frequently occupied.
But...I never have really worried about the cistern.
I wouldn't worry about 'cleaning' the cistern unless you are going to empty and recoat it.
If I was moving to a newly purchased home -- I would empty and recoat the cistern and probably never worry about it again.
Silt on the bottom does not mean the water is dirty.
With the filter system you described with UV I would not be concerned with either silt or frogs.
Bump up the chlorine to eliminate frogs and you should be good.
St. Croix resident since 2000