Rainwater Harvesting in Costa Rica – Viability and Costs

Rainwater Harvesting &

How it fits into Green & Sustainable Methods

We have visited this subject at various times over our years in Costa Rica.  It recently resurfaced again this past week due to questions directed from one of our readers and a prospective home builder.  It is far from uncommon for a client to spur on an investigation into a product, method or concept or in essence to bring such to the forefront of thought.  Hence once again I thought this subject more than warranted a post/article for others to, pardon the pun, harvest some knowledge from.  Thanks Tim for spurring me into action to answer questions and concerns of many other followers here on this blog.  Before we get started let’s get it straight as to what is priority one regarding any discussion or decisions being made with regards to sustainability.  Consumption rules the game whether we are talking water or electricity.  First control your use then deal with where your supply is coming from.  So for this discussion about water it goes without saying that one MUST USE low volume flush toilets that have come a long way in the last 15 years, as well as shower heads and sink taps with aerators and flow controls and never aerial spray your garden so as avoid throwing your precious resources down the drain or evaporating.

A Dose of Reality:

The data, according to The Washington Post, provide the most compelling and detailed picture yet of the status of vital water reserves hidden underneath the earth’s surface.

The paper further reported:

Twenty-one of the world’s 37 largest aquifers — in locations from India and China to the United States and France — have passed their sustainability tipping points, meaning more water was removed than replaced during the decade-long study period, researchers announced…. Thirteen aquifers declined at rates that put them into the most troubled category. The researchers said this indicated a long-term problem that’s likely to worsen as reliance on aquifers grows.

For some time, scientists suspected that humans were exacting a toll on the globe’s underground water supply. However, the NASA data and study were the first to actually detail major aquifer draw-downs as they struggled to keep pace with agricultural, human need and industrial demands.

“The situation is quite critical,” Jay Famiglietti, senior water scientist at NASA’s Jet Propulsion Laboratory in California and principal investigator of the University of California Irvine-led studies, told the Post.

Learn more: http://www.naturalnews.com/050422_aquifers_worldwide_drought_NASA_data.html#ixzz3g5g8W6zu

What happens when your water just disappears?

The Costa Rica feast or famine climate does indeed lend itself or demand one pays attention to water resources when we go from bone dry for a good part of the year to swimming up to your neck in water.  The following is a perfect example of how critical this issue can be in the enjoyment of your home and of course security of your investment in such.  The Guanacaste is the worst/best situation to employ rainwater harvesting.  A perfect example is the house we live in at Playa Conchal while doing our build at Playa Grande.  I have had to haul water 8 kms from our build site to our home as there is next to zero water in the two wells of this project.  One well goes dry by January and the other only produces maybe 10 – 20% of the needs of the project from January until the rains start again.  This is a very dry part of the north Guanacaste in the first place at about  48″ or 1.2 m of annual rainfall but this tough environment has been considerably aggravated by the sheer stupidity of MINAE (environment ministry in charge of water wells).  Less than 2 kms from this home is the Reserva Conchal Resort which has a few hundred condos plus employee housing along with an 18 hole golf course.  As many will know a golf course in this kind of hot and dry climate consumes a massive amount of water and in this case all of it comes from the aquifer since their is exactly zero rivers or lakes in this area.  To appreciate how insane of a move this was lets look at a typical California golf course of 110 acres normally consumes about 90,000,000 gals of water a year.  So that would equate to enough water to feed 4,500 homes for 5 months of the year at 265 gals per day per home.  Most assuredly there is not that many homes within the reservoir of Reserva Conchal’s wells, so lets just suffice to say a perfect example of, “TOTAL INSANITY!”

So MINAE issued licenses for the project to drill how many deep wells to provide the water to this one project while starving all the neighboring homes with shallow wells from getting water during dry season.  Surprisingly anyone I have talked to does not quite draw the connection between the cause and effect of what Reserva Conchal did.  If your neighbor, who could be 5 to 10 kms from you, bores down into the aquifer below your wells they get the water prior to it reaching up into the pump zone of your well.  In essence you are left with the hind tit, as it were, with zero or next to zero water available for 70% to 90% of the dry season.

The aquifer is typically just like one huge sponge so the water will move around in it would through  the easiest path horizontally thanks to good old gravity.  Hence why the offending water pig could be a long ways away from you and your dry well.  Also way out of sight and mind but just the same when those with deep enough pockets drill down further, than those with less money and resources, will get first dibbs on what water is available.  Yes an incredibly stupid and short sighted use of scarce water resources.  This is even more offensive when one considers that the state owns all water resources in Costa Rica regardless to who owns the land above it hence why you need a concession (license) prior to putting a well into service for any use.  In many circumstances you will never ever get such a license if you are too close to another well or have an alternative water supply like A y A or an ASADA.  (water cooperative)  Somehow Reserva ducked this or MINAE was grossly incompetent or paid off or more likely politically influenced to make bad decisions by the original developers where water rights were forgone by the fact that MONEY TALKS!

This is a perfect example of how water can so drastically affect your investment.  When this reality hit us hard in April I saw the situation and advised our client that his home in this waterless project is of seriously diminished value.  No one will buy in this project at  replacement value once anyone tells them about the water situation.  No one in the project can use or fill their swimming pools during the summer which happens of course to be the rental season hence many prospective vacation rental clients will just not rent if they can’t use the pool.  Worse yet any of the empty lots in this project cannot ever build because the administrator CANNOT very well issue a water letter that is required in order to get a building permit from the municipality.  Hence those lots are basically worthless or worse a liability with ongoing HOA fees assuming the owner is stupid enough to pay expenses on what is in now in essence nothing more than pasture.

This leaves the affected neighborhood in this pickle with but five choices:

  • 1. Sue Reserva and the government for blatant stupidity or breach of state law                                           = waiting 10 years for a process to unfold
  • 2. Haul water at $452 a load for 12,000 ltrs / 3,174 gallons (24 days of use) = $2,825 yr                -Take note the cost of trucking versus water from AyA would carry a bill of $20.40
  • 3. Harvest 20,000 gal of rain water and store it in an $8,000 tank = payback 2.8 yrs
  • 4. Build a desalination plant for a few million
  • 5. Learn how to do a really good rain dance 🙂

Now let’s move onwards with getting more into the green concept and more details on rainwater harvesting as that is really the only economically viable solution to this kind of situation.  This is hardly a new concept for me from having grown up on the prairies where water is a rather scare commodity with an annual rain fall of a mere 14 inches (35 cms).  Almost everyone out on the farm had cisterns to hold rainwater as well as many of the older homes in town did as well.  This feature did wain out over the years as far as new homes were concerned but let’s not assume the more modern methods are better or more sensible and often a complete opposite of sustainable.

While on this subject aside from the universal availability I also suspect many readers have no idea what soft rainwater is actually like to use in your home.  Softwater is far better to wash with for both bathing and laundry and actually requires substantially less soap to be used to get the same cleaning effect.  However it is not something one wants to drink due to the lack of minerals which makes it far less than tasty.  Although minerals is what makes spring water taste so good but the lack there of in rain makes it not suitable for drinking nor healthy when we aren’t getting those minerals in our daily dosage.  A further benefit to that lack of minerals means the whole water system including showers and toilets which all require way less maintenance over the years as there will be no buildups of mineral deposits anywhere.  Very hard well water always causes drastically more maintenance by shortening the life cycle of all components to the water system.

Also the reality is that the actual potable water use in a home is a minute part of the total water consumption (-5%) hence it is not actually expensive to acquire your favorite drinking water from a spring or even using horrifically expensive bottled water.  Another health benefit to having your own drinking water supply is that it would never have chlorine in it which of course no one should be consuming in any way shape or form.  Those using such a system like this will actually have parallel systems where a mini system feeds the cold water of the kitchen, ice maker and possibly vanity sinks whereas the major system will feed the toilets and showers and gardens.  With our PEX networks this is no more expensive since we already have individual lines to each service.  It will require more manifolds but each being smaller and a second pump for the potable water however these are cheap pumps due to the low demand hence a maximum of 1/2 hp which would run for typically 10 to 20 years.  It would require a second pressure tank but again a small one is all that is required once again due to the low demand.  The big issue however is that this type of dual system is something that in all practicality HAS TO BE DONE during construction.  Modifying an old system not configured in this way is what is expensive as well as being a royal pain in the ass to actually accomplish.

This type of water system also allows you to keep your personal vegetable garden growing during summer if your home does not happen to be parked by a full season river or creak.  The one caveat to that is that you have to use an underground weeping water system as above ground watering has an 80% loss factor from evaporation.  It would be nonsense to oversize cisterns to catch extra water that you only end up throwing away via evaporation.  Its not like Costa Rica needs to raise the humidity level any more.  Also on the typical larger sized lots our clients have we always position the septic leach field so that it provides the underground water system to feed the garden whether that be just to keep a year round green area and/or to feed veggies.  Also the extra nutrients that are carried along with septic run off in the field means anything growing above that field will grow like crazy, way beyond the norm.  In essence the fertilizer is carried with the water into the leach field.  Basically killing two birds with one stone naturally.  Yes there is those who push for recycling wash waters however along with such comes a drastically more complicated system both for installing as well as for maintaining.  Just using the wash waters to keep a perpetually green area and garden space does indeed provide a simple to install and maintain system not to mention a very pleasant environment.  After all one of our greatest benefits to living in Costa Rica is this green garden ambient!

In any zone where there is scarce water resources this is an absolute no brainer by simply using long term planning in your home and yard’s infrastructure.  Few people realize the incredible amount of water that actually can been caught off of a roof in Costa Rica.  Oh and NO we do not need a license or are we in any way restricted from collecting water as has become a bizarre but common fact in the USA.

One of our typical roofs running around 2,152 sq. feet or 200 m2 will catch the following amount of water. Take note that this is total roof area included the eaves, carports and terraces so this does not mean these stats are from a big home on North American Standards as far as in wall standards are concerned.

  • North Guanacaste         = 240,000 ltrs or   63,492 gal
  • Central Valley                = 440,000 ltrs or 116,402 gal
  • Jaco                               = 600,000 ltrs or 158,730 gal
  • Manual Antonio              = 700,000 ltrs or 185,185 gal
  • Dominical                       = 900,000 ltrs or 238,095 gal

Most homes would consume 180,000 to a max of 360,000 ltrs per year depending on the person load as well as your habits good or bad.

Your location in the country will affect how long your dry season is as well hence most certainly will affect the size of storage cistern one would require.  In general for sizes of any significance forget plastic tanks on the basis of cost as well as cosmetic factors.  Plastic works for small tanks 10,000 ltrs or less is their viable range.  Plastic cannot go in the ground either as they will easily collapse when empty plus you most likely do not want to look at these in your yard hence you are going to have to hide them away somewhere which will mean more piping costs.  Another  big problem on most sloped lots is to actually find any space for them especially if you need 5 to 10 of these.  Then the simple fact is that they cost about $.60 per gal to purchase which is 50% more than concrete.

Contrary to this I only use monolithic concrete tanks for their strength and much higher resistance to  seismic activity, NEVER BLOCK.  These can be buried underground and hidden from eyesight yet close to the house in the garage or driveway where the top can double as parking space as well as the top of the tank.  Also makes it easy to send the water into them and to retrieve it as well by your water system.  These tanks run around $.40 per gal depending on the configuration as the larger the tank the more economical it becomes simply via scales of economy.  To be able to survive for a 5 month dry season with a 132 gal or 500 ltr per day water habit will require a 75,000 ltr or 19,841 gal tank which will run you right around an $8,000 budget.  Take note though, if you have A y A water available at current rates it would take 25 – 35 years to pay off this tank from regular water bills and that is with building in a cost of living factor as their bills will indeed go up however I doubt the bill from the sky will do so.  So this option is for where there is a water shortage during dry season or simply for those who want to be self-sufficient.  Again all of this is only even remotely practical if done as part of a new home building process as a retrofit is going to double to triple your costs.  Reality is though that anyone with tanks of this size will most likely never ever have a use for any public water system and most people once on soft water have no desire what so ever to go back to mineralized and chlorinated water.  Plus wise people know that whenever it is possible to avoid chlorine will do so for long term health concerns by avoiding this known free radical.

In essence rainwater harvesting proves to be sustainable in all aspects of environmental concern, independence, better quality of life as well as personal health improvement.  Instead of saving for a rainy day you are saving for all those dry summer days of enjoyment.

As always feel free to post questions, clarifications or comments below or via email.

The following is a perfect example of opening up this discussion to our readers:
On Jul 10, 2015, at 9:26 AM, Chris wrote:


Great article once again Trevor! Speaks directly to the problems we deal with in Avellanas – the Avellanas water woo’s – is what they call it, yes there is a name for the water shortage in Avellanas, lucky us!
We will plan on the 20K tank, as the neighbors  have all suggested as big  of a holding tank as possible. According to them, if everybody had large tanks and ran from those, then the water shortage during dry season would not be an issue. So we were already planning on it.
My reply:
Yes it was indeed time to address this issue I just had not thought to put it in writing until our member brought it front and center which is of course how lots of our discussions, investigations and articles get started is from the shall we call it group inquiries and discussions.
Yes you do indeed make a great point that I had forgot to include in the first part of this post. If more people had tanks then the public system/wells would not be so overtaxed hence there would be something more than 2 drops in the line, a good point desperately needed to added to this debate.
This brings up a very significant issue on new builds as each one is of course adding even more load onto the already commonly over taxed systems.  This is in essence also a moral question too if one keeps on doing the same stupid things the situation will never get better since….
No rain drop blames itself for the flood, no snowflake blames itself for the storm and no new pipe blames itself for the dry well, hence each of our readers can blindly choose to add to the problem.  Each of you can choose to be part of the solution or part of the problem.  This is even further magnified since many of you are building in a system that is usually serving many Ticos who have quite limited resources.  They cannot afford an $8,000 tank hence have a reason to be irritated when you tap into their system after the issue of the famous water letter, which in this case would really be blatant bullshit if one knows very well there will be a shortage come late dry season.  I would submit it is not fare nor reasonable to tax these systems further when you can make a bigger and better and more logical plan.
Few builds cannot be adjusted to budget this critical component into the home especially since it is in all reality the most critical of all infrastructure components to any home.  I think my personal example at Conchal clearly demonstrates that reality.  Any home placed in the kind of environment where there is seasonal dry wells with water shortages without rainwater harvesting cannot even remotely be considered “GREEN” or socially responsible to your new neighbors.  Can you be considered a good new neighbor if you tap into their very limited precious resource???  Please also keep in mind the fact that all of these rural ASADAS barely meet their bills so they just don’t have government support or the capacity to drastically increase this infrastructure.  Also with the much longer distances involved the piping and pumping costs are verrry significant hence even more reason that water tanks are really a far more practical and economical solution to this problem.  And much faster to implement with zero bureaucracy involved.
I am adding another subject in here that is highly related to rain hence I am tagging it in here while you are thinking about rain.  It has to do with those gutters and how to keep them clean.  This also more than slightly relates to those that want to be doing rainwater harvesting as you certainly don’t want tons of organic crap ending up in your water storage to decompose.  Needless to say Costa Rica has great capacity in burying you in leaves.  Secondarily you may well have more enjoyable things to do that to regularly get up on your roof to clean all this junk out.  However the really big issue is as far as this thought process goes is what is your situation 20 years from now.  When you retire you are most likely quite capable of cleaning your gutters but down the road can or should you be up there in your advanced years.  It reminds me of a story from my best Tico friend Giancarlo who told me about his dad who was up there doing exactly that in Escazu after his odometer had clicked over 80 years.  He does a cartwheel off the roof ending up on his head.  The good news was that after an ambulance ride to a social hospital who checked him out first and his wallet a distant second they found no severe damage.  Of course his kids wanted to kick the old fools ass for being up there in the first place.  Yes it is good news to be capable of such a task at 80 but just the same a job possibly better left for the younger and more agile.
Hence the end of this story is I am bring in some stainless steel gutter guards that will filter out all the crap and let the water into your gutters.  I have never seen anything in Costa Rica to do this and just a simple screen DOES NOT WORK whereas these patented ones do.  They are going to run about $5 a foot I estimate but a small price to pay for something that A) works and B) lets you amuse yourself with better things and C) keeps you the hell out of the hospital or better yet the morgue!



Trevor Chilton

About Trevor

I have lived in Costa Rica for 19 years and have been active in real estate development over that period and construction in general. I am a qualified Journeyman carpenter and cabinetmaker from Canada. My current focus project is building custom green homes and housing packages all built out of SIPs or Structural Insulated Panels.


Rainwater Harvesting in Costa Rica – Viability and Costs — 8 Comments

  1. Is there no “in between” solution like having a smaller tank on top of the roof to use for showering and washing clothes during the rainy season to preserve the city or co-op water?

    What about pulling water from a small quebrada or spring on one’s land also as a way of maximizing the available natural water instead of using water from a municipal or rural system?

    • Jim,
      Thanks for your comments.

      Well you can’t put it on the roof since last I checked water does not run up hill well at all. Sure you could do that to avoid using water and the ensuing bill and no doubt some people do so but it would be in a serious minority as far as I have seen. This does require a tank, a pump and pressure system to do which would pay for itself over time but that is another reality that stops people. Also the fact that it does require a dual system of potable and wash water when in fact the homes never have a dual system as I described. It does require some forward thinking and planning which most fail miserably at. Which of course is exactly why the article was written in the first place. Now this is not to pick on Ticos however simple reality, in my experience, is people who live in the tropics hence do not have things like seasons to force them to plan and be organized or they will freeze to death or starve come winter. Those of us who come from such climates view this planning as a natural course which is indeed an exception here, far from a rule. They tend to ignore things like maintenance bills hence will do things that are actually far more expensive within a relatively short period of time. Eg. Like why would anyone buy roofing in galvanized versus baked enamel that is better and cheaper than the galvanized plus paint from a can that only peels in a few years. Talk about lack of planning or waking up to simple reality.


    • Absolutely nothing stopping one and simple logic would dictate you should do that but there is a lot of property that does not have flowing water 12 months a year. Also again easy, convenient and not requiring capital input is what does stop a lot of people. Sadly if that creek runs through a low income neighborhood you don’t want that water as they also dump a lot of wash water and contaminant in those or in farming areas lots of cow dung ends up there as well. Another big reason for rainwater harvesting is the purity of it provided you stop those cows from craping on your roof. Also those who use minimal water do have quite small bills. Now why more businesses don’t do this is even more bizarre as normally they do have a lot of roof and their water bills are double to triple of residential due to the pricing structures that A y A same as ICE where both have the same policy where businesses are in essence subsidizing especially the low income class.


  2. I meant to say “on the roof or on a tower type structure of wood or ?” in other words, a cheaper smaller semi-solution instead of a big project like one would need in Guanacaste.
    Why don’t people in Costa Rica gather the rain water as common method of utilizing the rain?

  3. Trevor,
    My big question is what kind of roofing materal is best for catchment….
    ” what on your roof will be in your water ”
    Great articles ,please keep them coming

    • Pretty much all the roofing covered in the report will be fine with one exception Asphalt Shingles royally suck in this aspect. Yes we used water off of thousands of these roofs up on the prairies but then we did not know better. The grit and especially the asphalt oils wash off the roof and plug up gutter screens etc especially the ones that actually work! Some of that residue is going to end up in your water. DAH! Hence another nail in the coffin of shingles as an option.


  4. Very interesting and timely article. Wish I had indeed built a rainwater tank – however 3 years ago when I built the (now) 3-year long drought in Guanacaste hadn’t yet reached critical proportions and the neighborhood wells were in good shape. That said, I found your take on your Playa Conchal neighborhood’s lack of water quite interesting. First, I don’t doubt that the Reserva Conchal’s usage *may* be starving out the surrounding neighborhoods. Therefore their recent announcement about building a desalinization plant in conjunction with a new hotel is most welcome.

    However, I actually live in the Conchal neighborhood that you and your construction crew of 9+ guys have been residing. Water is indeed tight, as it is all over this area, and it is rationed so that the well is turned on for a few hours every other day to fill our storage tanks. I have NEVER run out of water, except once when my garden hose sprung a leak and the hose bib was accidentally left in the “on” position.

    If we had the uncollected HOA money, we could easily afford to perforate our wells to a lower depth or even install a huge rainwater catchment system to serve as a backup for the entire neighborhood. Either solution would likely solve a huge portion of our water problems.

    Incidentally, your landlords haven’t visited in years and years and their pool has remained empty – whilst the other owners’ pools have remained fully usable, if low at times. Perhaps their pool could be converted to a rainwater storage tank. At the moment, it’s simply a scum-filled hole that the HOA has to periodically dump bleach into during rainy season to prevent it from becoming a Dengue pit that endangers the health of the other neighbors.

    • Sarah,
      Thank you for the note. I have only one disagreement with your comments, there is no “may” about the affect of Reserva Conchal it is elementary hydrology science. I am amazed that it appears so few draw that connection between cause and effect. Many in the neighborhood don’t want to point fingers due to the economic impact the project has in the community but that does not negate the sheer insanity of a golf course in the middle of a drought area. Gee just ask California about this issue! I have been told that five projects have the same problem as does Mata Palo and Brasalito all of which are well within Reserva’s thirsty underground reach. The news about another hotel and using a desalinization plant is rather interesting indeed however they don’t really have an option. Now that people are seeing these effects if they were about to put another heavy load on the aquifer I suspect there would be hell to pay. Also in these ensuing years water regulations and enforcement have changed drastically as this is no longer the wild wild west, so even with their economic clout I have my doubts and certainly hopes that the same errors would not be repeated again. Also the current owners do not have the political clout that Florida Ice and Farm did and does today.

      I have no doubt that if there was a solution to the water issue it would certainly help the financial situation of any and all affected projects however it is kind of a chicken and egg situation. Which comes first. What I do know is your investment is diminished, no new owners are going to come to help out financially since they can’t get permits to build with and those sitting on land are going to get to do exactly that, sit on it, until something magical happens. What I do know, as I stated in the article, those who are building now cannot consider rainwater harvesting optional equipment to their home. One of our new clients has already stated they have to do this at Avillanas as the same troubles abound.

      Also a rather glaring example of human insanity in this current situation of having a swimming pool that can’t be used in high season to only become a breeding ground for Dengae come the rainy season. However I do have their pump fixed now to reinstall so that we can keep the water out of it but without question your comment is most astute as it would be far more valuable as a tank than an unused pool!!!



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