Rainwater Collection Systems

[EOTE]

I've gotten so many questions and comments on our rainwater collection system that I decided to create a new thread to address the idea of rainwater collection and some of the technologies and equipment that goes into making a successful system.  I will start with explaining some of the thought process that went into our system and provide a tour of the system along with things that we could have done better and things that were successful.

I will try to address as many of the issues as I can and invite those of you that have or want to have a rainwater system to weigh in with your experiences, questions and comments.

Please feel free to join in and share your experiences as well.

[EOTE]

We decided to design and build a rainwater collection system about 3 and a half years ago.  The idea was spawned by looking at the costs and economics compared to well water and other options we have.  

We have a water district here that we could buy water from.  Back in the 70's and 80's whomever owned this land had water supplied from the water district.  However, for us to take advantage of it, they would have to bring in a new line (and charge us for it) and then whether we used it or not, it would be a base price of $24 per month.  The cost per gallon was pretty high to boot so we would spend hundreds a month on water.

We also have two wells that we discovered on the place and both were damaged by the bulldozer that cleared an area for them to sell the property.  They cleared about a quarter of an acre initially but drove over the large diameter well and ran into the well casing on the small well.  It was bent over and crumpled.  3 months ago when I rented an excavator I decided to dig around both wells.  The cased well had a 6" casing and the other one was two feet in diameter and was lined with cement pipe in 2' long sections.  The bulldozer crushed the concrete cap and pushed it down about 4' into the well where it is currently lodged.  I dug around the well enough where I can now remove the broken first 2' section and maybe get an anchor bolt put into the concrete cap so I can pull it out.  The well is probably a shallow well of 40 to 50 feet.   According to the neighbor, shallow wells could dry up during some of the dry spells.  The 6" cased well was probably in the neighborhood of 200' deep and probably put out between 5 and 10 gallons a minute when it was active.  Unfortunately, I did not see the benefit of remediating the cased well so I pulled the well casing (only 10') and first section of pipes and left the rest in the ground.  I covered it over so it is no longer an issue.  So potentially, I still have one well I can remediate.

We also inquired with a well driller to drill a new well but were not encouraged by both the cost and the potential yield from the well.  Neighboring wells are around 200' to 240' deep and don't produce more than 5 gpm.  The starting cost was around $7,500 and could go as high as $20,000.  I remember stories of well drilling in Montana during the early 1900's where the wells were drilled by hand.  One story goes that the guy (hand) dug a well 300' deep and never hit water.  He ended up moving about 50' and dug another well almost as deep before he hit some water.  Well drilling is kind of a crap shoot.  There are no guarantees you will find water.  As a side note, when I drilled a 4" well for my greenhouses in Montana we hit an underground river at 50' and could pump 100 gpm from it.

So this information affected our thought process in deciding on rainwater collection.  We checked with the state of Texas and we are free to collect rainwater.  In fact we are encouraged to and if we had been in a municipal district like Austin we would have gotten rebates from the city for doing so.

When I looked at what it would take to put in a rainwater system it was pretty simple.  Think of the early 1900's where lots of houses had a cistern in the basement.  That was their water supply complete with leaves, bird poop, frogs, bugs, etc.  We wanted to improve on that concept and researched systems and designs.

The basic components are pretty simple:  A collection area (i.e. roof), a storage area (tanks), plumbing to get the water from the collection area to the storage area, and then additional plumbing to get the water from the storage area to where you want to use it.  Add any bells and whistles you want to make it more to your liking (like water filtration).

This shows the 3 water tanks with the connection plumbing on the bottom that ties all three tanks to the water system in the barn.


 

This shows the leaf separator below the gutter downspout and the first flush plumbing.



 

This shows the plumbing into the barn as well as the sight gauge (clear PVC) so you can see the water level in the tanks.



 

We installed an Aquasana water purification system which consists of a 30 micron pre-filter, a 1 million gallon rated carbon filter, a 10 micron post filter and a UV light sterilizer which the water passes through.  I have a 3/4 hp water pump that is pressure activated at 30 psi (low) and 50 psi (high) and two pressure tanks, a 26 gallon and a 110 gallon (not shown in the photo).



 


So our system consists of a 40' x 72' barn roof for capturing the rain.  It's on a 2/12 pitch so the effective surface area is about 2,950 square feet.  

Our historical usage in our home in central Texas including outside irrigation was an average of 3,300 gallons per month.  I wanted to have at least 5 months of historical water usage as my storage capacity so 3,300 x 5 = 16,500 gallons.  We opted for 3 - 5,000 gallon plastic tanks because of the cost and warranty.  The 3 tanks cost me about $5,000.

The plumbing was pretty straight forward using 4" PVC sewer pipe and fittings.  We mounted the pipes directly under the eves and used a separator designed to remove debris from the rain water.  So the water ran out of the down spouts through the separators into the 4" pipes which then flowed to the tanks.  Before entering the tanks we put in something called a "first flush" which collects the first 10 to 20 gallons of water washed down the pipes into a "holding" pipe  so it separates what is typically the dirtiest water from the rest of the water.  The reservoir the first flush water runs into has a floating ball that stops the flow into the reservoir when it is full.  The rest of the water the flows into the tank which also has a basket screen at the entrance of the water pipe.  Finally there is an overflow pipe from the tanks that allows water to exit the tanks if the tanks are full.  Our tanks are also tied together so the water level is self leveling between the three tanks.  (We plumbed the water to only run into the outside two of the three tanks so the 3rd tank fills by the water self leveling).

Because the area where we live generally has several inches per month in rain, we felt we would have a ready supply to refill the tanks as the water was used.  This area gets an average of 48 inches of water per year which for our roof could produce up to 84,000 gallons a year of captured rain water.  The roof generally produces about 1600 gallons of water for storage from an inch of rain.  In the last 3 years we have never been down more than 1500 gallons which is encouraging.

So that's the basics of our system.  

[Walnut Beast]

Very interesting 👍

[clearcut]

I want to convert an existing swimming pool into a 28,000 gallon cistern for landscape irrigation and fire protection. Build another smaller swimming pool. We have utility district water for domestic use. When we had too much lawn it cost about $200-300/month in the summer to irrigate. Wife is tired of the rather brown, dusty - though exceptionally low maintenance - weed patch where her lovely green - exceptionally high maintenance - turf used to be. 

In the event of wildfire, I want to put a wall of stored-onsite water, over the roof and around the house, as well as have a place for the fire truck to latch onto. One should alway invite the local firetrucks to visit your house - during a nearby wildland fire. Firefighters seem to prefer parking near reliable sources of water and an easy place to turn around. Working on both. 

Working on fire safe landscaping, got cited today. Inspector noted that work was in progress, but "if I see it today, I have to call it, today". Fair enough, now I have a due date and a list, before I just had a list. Pruning some dead and low branches, picking up the pile of dried daffodil leaves that I was raking - when she came to inspect, and the pile of cardboard - going to recycling tomorrow, piled too close to the house. We did confer about my windbreak shrub, especially if I can get a sprinkler on it - it can stay.

Have not done the roof calculations yet, but yours gives me hope. We get an average of 38" per year with wild fluctuations. Roof, basketball court, deck, and the 20x40' pool itself, probably covered with a tarp of landscape fabric. Eventually solar panels.

Landscape and fire only, so I won't need your level of filtration. I thinking a gravity fed, sand pre-filter, and the pool filter (DE) for the swimming pool water. I have a spot that should work. Solar panels for pumping, just starting that research.  

Thanks.

[EOTE]

I want to convert an existing swimming pool into a 28,000 gallon cistern for landscape irrigation and fire protection. Build another smaller swimming pool. We have utility district water for domestic use. When we had too much lawn it cost about $200-300/month in the summer to irrigate. Wife is tired of the rather brown, dusty - though exceptionally low maintenance - weed patch where her lovely green - exceptionally high maintenance - turf used to be.

In the event of wildfire, I want to put a wall of stored-onsite water, over the roof and around the house, as well as have a place for the fire truck to latch onto. One should alway invite the local firetrucks to visit your house - during a nearby wildland fire. Firefighters seem to prefer parking near reliable sources of water and an easy place to turn around. Working on both.

Working on fire safe landscaping, got cited today. Inspector noted that work was in progress, but "if I see it today, I have to call it, today". Fair enough, now I have a due date and a list, before I just had a list. Pruning some dead and low branches, picking up the pile of dried daffodil leaves that I was raking - when she came to inspect, and the pile of cardboard - going to recycling tomorrow, piled too close to the house. We did confer about my windbreak shrub, especially if I can get a sprinkler on it - it can stay.

Have not done the roof calculations yet, but yours gives me hope. We get an average of 38" per year with wild fluctuations. Roof, basketball court, deck, and the 20x40' pool itself, probably covered with a tarp of landscape fabric. Eventually solar panels.

Landscape and fire only, so I won't need your level of filtration. I thinking a gravity fed, sand pre-filter, and the pool filter (DE) for the swimming pool water. I have a spot that should work. Solar panels for pumping, just starting that research.  

Thanks.

That sounds like a great project.  After all the devastating fires in California I hope the powers that be recognize that they have to balance between logical fire prevention and the previous "do nothing" approach.  You are doing a great job of coming up with a good preventive method.  Gravity feed from the collection areas will generally work well for roofs.  For other areas it depends on their location relationship  with the pool.  Use some kind of leaf/debris separators so you can catch all the big chunks before it gets to the pre-filter, otherwise it will clog quickly.  You wouldn't believe how many leaves and pine needles we get on a roof that is 50' from the nearest tree.
Consider using trench drains around the basketball court to collect the run off.  Depending on how it is sloped you might be able to put them along the side where the water runs off.
Do you have to get permits in California to do rainwater collection?  How much is the local government going to look over your shoulder?

[clearcut]

Excavation for "firesafe landscaping, including renovation of the existing irrigation system" is mostly complete except for a lot of hand digging. Too hot, too many thing breaking, and a real work - hard deadline on 6/30 have slowed the project. 

I'm still researching with the county. Offices have been locked down, and are likely to lock down again soon. My idea is non-traditional - so it will take some convincing. Your set up of prefab tanks on a concrete pad is easier for planning to wrap their heads around - and may be the final solution. 

While there is information on the county web site regarding potable water collections systems and fire protection requirements for new subdivisions, there is no real mention of the specifications for rainwater collection.  Local fire chief is happy with any system that his truck can get to safely. and connect to easily.

Rainwater harvesting is legal. Getting it filtered and tested to potable would be a much higher standard to reach. Our utility district water tastes and tests just fine.

My site is well suited for collection. Gutter flows can be easily directed to the soon-to-be cistern. Runoff from the other hard surfaces also flow in that direction. Gutters are screened, and by-pass filters are factored in. I understand quite well the power of the wind to deposit fuel on my roof.

Fire insurance is getting canceled again. Would rather spend the money on actual protection rather than reimbursement following loss.

Thanks for the encouragement. 

[JRHill]

The folks who dug our well have a junk pile of failed components. A good part of the pile's contents are 80g fiberglass WellMate pressure tanks. They have to pay to get rid of them so were more than happy for me to take as many as I wanted. I took only the old style cause the piping is just thick wall 1 1/4" to make up the adapter to chain them together.

I pull out the bladder by laying the tank on its side and hold it down with the Kubota's loader, tie a pinching loop to as much of the bladder as I can get out by hand and then slowly pull it out with an ATV.  BTW, I cut a few inches off the bladder so the air and any water can escape while its coming out. Before unscrewing the Schrader valve on the top, be sure to remove the core. Before reassembling the bottom I extend/lengthen the tubing with a Tee so I can connect each tank in a staggered series with black tubing.

I've got around 1200 gallons of storage from the gutters of the shop roof for low pressure garden water and water trough filling. All in all it didn't cost any more than the PVC fittings, glue, clamps, etc. There's about 20+ foot of elevation between the tanks and garden, pens, and an outdoor summer shower (wink).

We don't get much more than overnight condensation in the summer months so I backfill the tanks with our water well as needed. Our well is solar powered and can run continuously on a sunny day and still recharge the batteries at the same time. BTW, the old bladders are handy for miscellaneous uses but they only last a few years till the UV ruins them.

Also, I've gotten a few perfectly usable pressure tanks in case I need pressurized non-potable water away from the house.

[farmfromkansas]

Amazing difference in rainfall between eastern Texas and nc Kansas.  Instead of the yearly 48" you get there, we only get about 31 inches per year.  And some years are well below that. I grew up on cistern water, never even thought about above ground tanks. Maybe the amount of freezing weather we get keeps that from working here.

[JRHill]

Amazing difference in rainfall between eastern Texas and nc Kansas.  Instead of the yearly 48" you get there, we only get about 31 inches per year.  And some years are well below that. I grew up on cistern water, never even thought about above ground tanks. Maybe the amount of freezing weather we get keeps that from working here.

I almost mentioned annual rainfall as the reason for our tanks as we only get 16". We're in south central WA and in the rain shadow of the Cascades. As for freezing, even though last winter was warmer than normal we had the first freeze break in the storage. And of course it had to be right in the middle of the string.

I've been dragging my feet in fixing it as the dang rattlesnakes are bad this year. Even seen them by the pigs which is surprising. Any snake has a death wish getting around pigs, esp sows with piglets.

[JRHill]

Rainwater harvesting is legal. Getting it filtered and tested to potable would be a much higher standard to reach. Our utility district water tastes and tests just fine.

We are a long way out of any traffic or eyesight so can escape any legalities as to rainwater collection. Not even sure what the "law" is here and don't care.... Ditto on the RFD for water storage. We have a 3000g tank up the canyon a bit that by the trail that is suitable for potable storage and gets us 30psi from gravity flow. Not enough for the HW heater but is good for an emergency or RFD access. 3000g doesn't go far.
While rain water is free (when available) it is strictly for non potable use. I gave up on low pressure watering in the garden with it due to the never ending clogging of the in-line filters, sprayers, etc. with gunk and algae. We use it for free flow hoses only and sometimes even the shut offs have to be disassembled to clear a clog.
Fortunately our water well provides 13g/min of sweet water. A bit high in mineral but that's OK, it still tastes fantastic and certain mineral is important for taste. But we highly value no chlorine, fluorine, etc. And dang good coffee and drinking water (wink). I filter some water but only through coffee grindings.
Wife is a biologist. The chances of drinking roof water here are about slim and none. It can be done but at a high cost in equipment and risks. I wouldn't advise it if there are other resources available. But you do what you have to do.

[EOTE]

Rainwater harvesting is legal. Getting it filtered and tested to potable would be a much higher standard to reach. Our utility district water tastes and tests just fine.

We are a long way out of any traffic or eyesight so can escape any legalities as to rainwater collection. Not even sure what the "law" is here and don't care.... Ditto on the RFD for water storage. We have a 3000g tank up the canyon a bit that by the trail that is suitable for potable storage and gets us 30psi from gravity flow. Not enough for the HW heater but is good for an emergency or RFD access. 3000g doesn't go far.
While rain water is free (when available) it is strictly for non potable use. I gave up on low pressure watering in the garden with it due to the never ending clogging of the in-line filters, sprayers, etc. with gunk and algae. We use it for free flow hoses only and sometimes even the shut offs have to be disassembled to clear a clog.
Fortunately our water well provides 13g/min of sweet water. A bit high in mineral but that's OK, it still tastes fantastic and certain mineral is important for taste. But we highly value no chlorine, fluorine, etc. And dang good coffee and drinking water (wink). I filter some water but only through coffee grindings.
Wife is a biologist. The chances of drinking roof water here are about slim and none. It can be done but at a high cost in equipment and risks. I wouldn't advise it if there are other resources available. But you do what you have to do.

JRHill, if you're getting algae, are your tanks getting light inside them?  I have opaque black tanks and pvc pipes and never have an algae problem.  I am kind of curious as to the source.  Potable drinking water from rain water is actually fairly easy to achieve with the filtering systems that are available as well as the testing resources.  Mine has been tested for 189 different minerals and contaminants and it is so clean that it is almost like distilled water.  Even if the water comes off asphalt shingled roofs, there are filtration systems that remove the contaminants and make the water safe.  

[EOTE]

(This is a duplicate post to our thread Building our Dream Home a.k.a. Delusions of Retirement) 

This weekend we stubbed out all the rainwater collection plumbing for the house.  It was fairly simple; 6 - downspout stubs, 4 - exterior water spigots (one on each side of the house), and the associated collection piping.  The tanks have not been chosen but the site for the storage tanks has been (about 50' from the house).  We did not extend the plumbing to the tank area and won't until we are ready to connect the tanks.



 



 

The collection system is split to provide an even distribution of collection load (one half of the roof on each half of the system).
The water distribution system is 1" PVC and provides a single outlet on each side of the house.  We will place a pump, filter system, and pressure tank down by the storage tanks.  Probably something in the neighborhood of a 3/4 hp. pump like we are using in the barn for the potable water system.  We are looking at 4 - 3 to 4 thousand gallon tanks for non-potable storage.



 

[gspren]

Are there any easy/economical solutions to using rainwater in the northern states where freezing will happen?

[EOTE]

Are there any easy/economical solutions to using rainwater in the northern states where freezing will happen?

Igloos? :D :D :D


Seriously, I am not sure how far North that rainwater becomes ineffective to recover.  I remember in Illinois that older homes had cisterns.  But during the colder months the system would probably freeze up unless the tanks are in an enclosed and possibly insulated area (maybe below ground).  Freezing and thawing would require that any collection pipes can completely drain after a rain or would have to have something like heat tape around them to be activated when the temperature got below freezing.  
Are there any FF members in the northern US that have rainwater systems that can share their experience?

[JRHill]

Rainwater harvesting is legal. Getting it filtered and tested to potable would be a much higher standard to reach. Our utility district water tastes and tests just fine.

We are a long way out of any traffic or eyesight so can escape any legalities as to rainwater collection. Not even sure what the "law" is here and don't care.... Ditto on the RFD for water storage. We have a 3000g tank up the canyon a bit that by the trail that is suitable for potable storage and gets us 30psi from gravity flow. Not enough for the HW heater but is good for an emergency or RFD access. 3000g doesn't go far.
While rain water is free (when available) it is strictly for non potable use. I gave up on low pressure watering in the garden with it due to the never ending clogging of the in-line filters, sprayers, etc. with gunk and algae. We use it for free flow hoses only and sometimes even the shut offs have to be disassembled to clear a clog.
Fortunately our water well provides 13g/min of sweet water. A bit high in mineral but that's OK, it still tastes fantastic and certain mineral is important for taste. But we highly value no chlorine, fluorine, etc. And dang good coffee and drinking water (wink). I filter some water but only through coffee grindings.
Wife is a biologist. The chances of drinking roof water here are about slim and none. It can be done but at a high cost in equipment and risks. I wouldn't advise it if there are other resources available. But you do what you have to do.

JRHill, if you're getting algae, are your tanks getting light inside them?  I have opaque black tanks and pvc pipes and never have an algae problem.  I am kind of curious as to the source.  Potable drinking water from rain water is actually fairly easy to achieve with the filtering systems that are available as well as the testing resources.  Mine has been tested for 189 different minerals and contaminants and it is so clean that it is almost like distilled water.  Even if the water comes off asphalt shingled roofs, there are filtration systems that remove the contaminants and make the water safe.  

You've probably seen the fiberglass pressure tanks - they are painted over with gray or tan color. I suppose that bright sunlight could allow for some illumination inside the tanks. And for rain water being clean, I have heard of people using fresh, strained/filtered rain water to top off flooded batteries. I supposed it heavily depends of the area's air quality. But seriously, to me, it not worth shortening the life of a $3.5k solar bank.
As to the source of the algae, my gutters do have to be cleaned on oak leaves, pine needles, etc. each year. So I'm sure some amount of particulate organic material makes its way past two strainers and into the tanks.

[EOTE]

Rainwater harvesting is legal. Getting it filtered and tested to potable would be a much higher standard to reach. Our utility district water tastes and tests just fine.

We are a long way out of any traffic or eyesight so can escape any legalities as to rainwater collection. Not even sure what the "law" is here and don't care.... Ditto on the RFD for water storage. We have a 3000g tank up the canyon a bit that by the trail that is suitable for potable storage and gets us 30psi from gravity flow. Not enough for the HW heater but is good for an emergency or RFD access. 3000g doesn't go far.
While rain water is free (when available) it is strictly for non potable use. I gave up on low pressure watering in the garden with it due to the never ending clogging of the in-line filters, sprayers, etc. with gunk and algae. We use it for free flow hoses only and sometimes even the shut offs have to be disassembled to clear a clog.
Fortunately our water well provides 13g/min of sweet water. A bit high in mineral but that's OK, it still tastes fantastic and certain mineral is important for taste. But we highly value no chlorine, fluorine, etc. And dang good coffee and drinking water (wink). I filter some water but only through coffee grindings.
Wife is a biologist. The chances of drinking roof water here are about slim and none. It can be done but at a high cost in equipment and risks. I wouldn't advise it if there are other resources available. But you do what you have to do.

JRHill, if you're getting algae, are your tanks getting light inside them?  I have opaque black tanks and pvc pipes and never have an algae problem.  I am kind of curious as to the source.  Potable drinking water from rain water is actually fairly easy to achieve with the filtering systems that are available as well as the testing resources.  Mine has been tested for 189 different minerals and contaminants and it is so clean that it is almost like distilled water.  Even if the water comes off asphalt shingled roofs, there are filtration systems that remove the contaminants and make the water safe.  

You've probably seen the fiberglass pressure tanks - they are painted over with gray or tan color. I suppose that bright sunlight could allow for some illumination inside the tanks. And for rain water being clean, I have heard of people using fresh, strained/filtered rain water to top off flooded batteries. I supposed it heavily depends of the area's air quality. But seriously, to me, it not worth shortening the life of a $3.5k solar bank.
As to the source of the algae, my gutters do have to be cleaned on oak leaves, pine needles, etc. each year. So I'm sure some amount of particulate organic material makes its way past two strainers and into the tanks.

One thing to be sure of is that rainwater is not "clean".  The pre-filters I have are screens that prevent mosquitoes from entering so the mesh size is pretty good size.  That translates to sludge in the bottom of the tank from ash, pollen, bird poop, dust, and other bits and pieces that make it through the 2 pre-screens I have.  That is why I have the additional comprehensive filtering system in place.
As for algae, it needs light to grow so eliminating any source of light will help to prevent algae growth.  Of course, I might be wrong in that there may be a species of algae that can grow in the dark but I honestly have not heard of it.

[JRHill]

My whole use of the collection was to get what I could from rain or to collect (fill) during sunlight prime time. I'm not sure about the algae generation. But since the under ground lines are free from sunlight and they still get build up it would seem this can happen regardless of sun light. Case in point: an irrigation line was snagged with the backhoe causing me to splice and patch it. it had a bunch of grunge on the interior sidewalls that had to be cleaned out before re terminating the line. Of course, if the tanks were the source of algae then who knows ... its garden, pig, duck, goose, etc water.

If anything comes out of this it should be the testing like Mr EOTE referenced. Don't get sick.