Natural Pools

We at EcoBrooklyn engage in a number of exciting green building projects and experiments throughout the year, but with the hot months ahead at the top of our list is the natural pool for the show house and with its completion so close we can almost feel the cool, energetic, life infused water on our toes.

A “Natural pool” is more about incorporating nature into the design and functions of the pool, harnessing natural processes to maintain quality, swimable water and blurring the line between built and naturally occurring.

A healthy body of fresh water has a number of checks and balances that keep it in balance. A Natural Pool simply recreates these elements. Nature does the rest.

A Natural Pool has the swimming area and then another area called the regeneration zone. This zone contains plants and, most importantly, surface area usually in the form of gravel that microbes can live on.

The plants and microbes compete with algae for food and since you pack it with surface area the microbes beat out the algae. In essence you create an environment where food (leaves, soil, bugs, and other organic matter) is scarce, so what food there is becomes eaten by plants and microbes instead of algae.

The process is fairly flexible and can be as simple or complex as you like as long as you have a few basic elements:

-No chemical fertilizers/ pesticides used adjacent to the site

-Natural filtration system

-A variety of different plants, surface area and microbes to promote a balanced ecosystem

The beauty of natural pools

The primary appeal of a natural pool is the absence of the typical cocktail of harsh chemicals designed to kill pretty much everything in the water, except the swimmer more or less.

The second attraction is the positive ecological effect; this is something you can build with salvaged and recycled materials while helping to reinstate local/native ecosystems.

As with most things green there is a degree of time and thought investment not usually associated with the typical energy sapping, chlorinated eyesore.

there’s no competition really


Maintenance is still simpler and less expensive, but one needs to learn and follow a set of steps and rules, which as one grows with the pool these steps become second nature, or perhaps first nature…

Thankfully there are always pioneers braving new frontiers and providing the general populace with valuable resources and tools to implement in their own projects.  The Europeans especially have been at the forefront of the natural pools race for over a decade now. They have built massive public natural swimming pools that cater to thousands of people with great success.

beautiful design

wide range of options

Below is a list of websites and organizations specifically geared towards natural pool construction; they provide excellent technical suggestions for all types of designs and constraints as well as helpful trouble shooting for any problems that may arise.  Also they can provide you with competent local green contractors and builders in your area familiar with this sort of construction.

Eco Brooklyn hopes to become a leading natural pool installer in the New York area. We feel this is an excellent option since it adds so much to a garden, both for humans but for native wildlife.


-Michael DiCarlo

Gray Water Use in New York

Being a New York green contractor involves pushing two very important elements through DOB code approval:
1. composting toilets
2. gray water and rain water for flushing toilets.

We recently tried to get composting toilets approved for our Passive House in Harlem but it got shot down. We will persevere trying to get it legalized in NYC but for now it can’t be done legally.

Here is the latest on DOB code regarding gray water, as discused between myself, Joe Schaffer PE, and Victoria Ann Vele, Social Media and Water Research Intern and Benjamin Cole, Legal Intern, both for Living City Brooklyn Gowanus, Living City Block.


Victoria to Ben: Can you help me find NY laws and regulations for grey water use in residences? I think its illegal.

Ben to Victoria:  Here is what I found, below. The highlighted portion seems to answer your question, but it’s worded strangely.  (Does it mean lavatory gray water can only be recycled from commercial office buildings or does it mean all gray water must be lavatory gray water from commercial office buildings?

From the NYC Construction Codes:

§ PC C101: Water Recycling Systems

C101.1  General. Water recycling systems shall receive storm water captured from roofs and balconies, condensate reclamation systems, gray water discharge only of lavatories from public restrooms in commercial office buildings, and the treated effluent from an approved black water treatment system as regulated by Department of Health and Mental Hygiene. Recycled water shall be utilized only for flushing water closets and urinals, cooling tower makeup and irrigation systems that are located in the same lot as the water recycling system. Recycled water shall be considered non-potable. Such systems shall comply with sections C101.2 through C101.12.

C101.2  Definitions. The following terms shall have the meanings shown herein.

BLACK WATER. Waste water discharged from water closets, urinals and any other fixtures discharging animal or vegetable matter in suspension or solution.

GRAY WATER. Waste water discharged from lavatories, bathtubs, showers, clothes washers and laundry sinks.

C101.3  Installation. All drain, waste and vent piping associated with gray or black water recycling systems shall be installed in full compliance with this code.

C101.4  Reservoir. Water captured for recycling purposes shall be collected in an approved reservoir constructed of durable, nonabsorbent and corrosion-resistant materials. The reservoir shall be a closed and gas-tight vessel. Access openings shall be provided to allow inspection and cleaning of the reservoir interior. The holding capacity of the reservoir shall be a minimum of twice the volume of water required to meet the daily flushing requirements of the fixtures supplied with recycled water, but not less than 50 gallons (189 L).

C101.5  Filtration. All water entering the reservoir shall pass through an approved filter such as a media, sand or diatomaceous earth filter. Filter may be installed in a sidestream arrangement sized to filter the entire volume of the tank at a rate equal to four times the recycled water in a one-hour period.

C101.6  Disinfection. Recycled water shall be disinfected by an approved method that employs ultraviolet or one or more disinfectants such as chlorine, iodine or ozone.

C101.7  Makeup water. Potable water shall be supplied as a source of makeup water for the recycled water system. The potable water supply shall be protected against backflow in accordance with Section PC 608. There shall be a full-open valve on the makeup water supply line to the reservoir.

C101.8  Overflow. The collection reservoir shall be equipped with an overflow pipe of the same diameter as the influent pipe for the captured water. The overflow shall be directly connected to the building house drainage system.

C101.9  Drain. A drain shall be located at the lowest point of the collection reservoir and shall be directly connected to the sanitary drainage system. The drain shall be a minimum of 4 inch (102 mm) diameter and shall be provided with a full-open valve.

C101.10  Vent required. The reservoir shall be provided with a vent sized in accordance with Chapter 9 based on the size of the reservoir influent pipe.

C101.11  Coloring. The recycled water shall be dyed blue or green with a food grade vegetable dye before such water is supplied to the fixtures.

C101.12  Identification. All recycled water distribution piping and reservoirs shall be identified as containing nonpotable water. Piping identification shall be in accordance with Section 608.8.

Victoria to Gennaro Brooks-Church: Does the highlighted portion mean that you can use grey water in toilets in commercial buildings only?

Gennaro Brooks-Church to Joe: Can you help me make sense of the gray water code? I says it is ok for commercial but not residential? And there is no mention of testing?

Joe: You’ll note that the system is required to use “approved” devices for filtration, disinfection, and dye injection.  This approval would come from DOB’s Office of Technical Certification and Research (OTCR).  OTCR recently released a technical bulletin covering water recycling and reclamation systems. This technical bulletin has the force of an interim code update; a full update is due out soon and will reflect the testing requirements noted therein.

The practical upshot of the technical bulletin is that a manufactured lavatory to toilet device (such as a Sloan Aqus unit), irrigation, and cooling tower make-up is allowed without testing, but any other in-building use requires a testing regime.  My interpretation is that this bulletin applies to any use (commercial, residential, industrial).


So…what does this all mean? My interpretation is that gray water through lack of any clear DOB documentation wasn’t illegal for flushing toilets. It basically flew under the radar. But now with the advent of OTCR attempting to regulate NYC gray water, which is a good thing, they have made it illegal or completely cost prohibitive, which is a bad thing. At least for the time being until the OTCR realizes your toilet is always going to be dirtier than any gray or rain water and the testing is silly.

Think about it, a toilet is a dirty place. Why do we have to have such strict water cleanliness levels to flush it? If a child plays in the toilet water, whether it be fresh city water, gray water, or rain water, you are going to have a problem. It is pretty irrelevant what the water source is (within the limits of gray/rain water) because once it hits the bowl it becomes contaminated anyway.

With this new regulation for testing you can’t just set up a functional gray water system (or rain water system) that feeds toilets in a Brooklyn brownstone. That is illegal now. You need go through the rigorous water testing process as outlined by the OTCR. At about $10,000 per year, the costs involved are too expensive for a residence. The testing may make sense for a large institution like a university, but only with the hope of showing the DOB that the water is clean enough and that testing is not necessary.

There are two things at play here. One is the early adopter home owner who understands the risks and benefits of gray water and chooses to install it without DOB approval and without testing. It is illegal but it is more ecological than the current arrangement of flushing with potable water (crazy!) and it does increase social acceptance of an important thing. I call it civil disobedience.

The second thing is large scale implementation of gray water. This is where it is very important that the DOB be on top of things. If gray water became widely used in NYC without DOB control you would have problems. Early adopter home owners is one thing but uneducated tenants in a large apartment building is a whole different thing. And that is the level the OTCR has to think. I call it the lowest common denominator.

So until DOB sorts things out and finds a working solution for gray water use in NYC, green building companies like Eco Brooklyn will just have to wait.

What is legal is rain water capture and gray water use for the garden. The basic concept is that water can leave the house but it can’t be used within the house. So you can’t capture rain water and bring it into the house for flushing toilets or showers. Likewise you are allowed to collect the house gray water and pass it to the green roof and garden. That is legal and a great second option to the flushing toilets with it.

It is perfectly legal to run the plumbing lines now, either for passing gray water to the garden or in anticipation for using gray water on toilets. To do this you simply seperate the kitchen sink and toilet drains (black water) from the bathroom sink, shower, tub and laundry drains (gray water).

The two seperate drains go to the basement where you combine them again and dump them both into the mains sewer. This prepares the plumbing for the gray water tank. Later when the DOB allows it you seperate the gray water drain and pass it into the gray water tank. You hook the tank to the toilet water line (that was also plumbed seperately from the other water line) and you have a functional gray water system.

Of course there is a lot more to it in terms of keeping the gray water from going putrid but that is the basic setup.

Hopefully it will be sorted out sooner than later. Eco Brooklyn is actively working with the DOB, if you can call it that, to increase their awareness of composting toilets and gray/rain water, even if it simply means we apply for the system and they reject it. At least they know it exists and people want to do it.


What Gray Water Systems are available?

Every Brooklyn brownstone should have a gray water system to feed the toilets, green roof, living wall and garden.

Unfortunately there are few systems to choose from. They range between $2,000 and $7,000 for the unit not including running the extra drains from the shower, bathtub, sink and washing machine.

Right now in the US the only only prepackaged residential gray water systems I know of are Water Legacy, Brac Systems, and ReWater. A fourth, produced by Water Saver Technologies, and distributed by Sloan Valve, is also available, but is not a whole-house system. It recycles the water from one lavatory sink for use in the water closet in the same bathroom. It seems to work ok but I’m not crazy about the concept. I rather a whole house system – less parts to break. The price is pretty good. A couple hundred dollars.

Several other systems, currently available in other countries appear ready to enter the U.S. market: Perpetual Water and Nubian from Australia, EcoPlay from the Netherlands, and Pontos (a subsidiary of Hansgrohe) from Germany.

There are a couple gray water systems for the garden. Matala makes a great one called Aqua2use. Waterwise does too. But they don’t work for toilets. Matala is coming out with one soon they say.

I have used the Brac system and they suck. All the other systems are ok but I’m not in love with them. The best is Water Legacy. But like most of them it is costly at $4,500.

Eco Brooklyn is working with an engineer and the Department of Buildings to build our own legal system. But it is slow going. For the time being we are stuck with making our own under the radar systems with early adopter clients. The systems work great and are affordable but they are still very much a work in progress.

Bromine as a Chlorine Alternative for Gray Water

We’ve been looking for a chlorine alternative for our Brooklyn brownstone gray water systems. Chlorine is not ideal because it gives off fumes. I’ve also read that when the chlorine molecules bond with the soil particles it alters the chlorine into a form called Chloramine that causes cancer. This is a concern if using the gray water to water edibles.

Here is what one site says . Granted the site is overly alarmist but you get the picture with this quote:

Chloramine is a toxin added to drinking water. It is a secondary disinfectant used by many States as a primary disinfectant. Chloramine is ammonia added to chlorine to make chloramine. Chlorine has been shown from animal and human research to cause breast cancer in humans. Listed in the MSDS industrial chemistry book with an “X” and to be used only in an emergency to attempt to destroy liver flukes and Cryptosporidium in humans. Chloramine does not have an antidote and is genotoxic, meaning DNA destruction and is a mutagenic, meaning it causes tissue mutations.

The EPA is a lot more forgiving of Chloramine saying that the benefits outweigh the risks but they still admit that animal studies have shown it causes cancer, albeit they us this as an excuse that the chemical is ok for humans:

EPA believes that water disinfected with monochloramine that meets regulatory standards poses no known or anticipated adverse health effects, including cancer. Most of the research on the cancer risk of monochloramine comes from animal studies using mice and rats. EPA’s regulatory standard for chloramines provides a wide margin of safety to offset any uncertainties in risk assessments.

So anyway the use of Chlorine is suspect in my opinion. I was a pool life guard for years when growing up. I was on the swim team etc. And I’m not dead. So of course our bodies can handle chlorine.

BUT our bodies can handle smokings, alcohol and car fumes as well. There are a lot of chain smoking alcoholic mechanics in the world who are doing just fine. Or what about small amounts of formaldehyde? Have your smelled your couch lately? Odds are it has some.

Just because our body can handle something does not mean we aren’t happier and healthier without it.

And that is why we are looking for chlorine alternatives to keep the gray water from becoming toxic.

An often touted alternative to chlorine is bromine. For example this site says:

Bromine kills bacteria the same way chlorine does, but while chlorine produces chloramines, bromine produces bromamines. There’s no need to worry, however, as bromamines are actually a disinfectant in their own right and are capable of killing bacteria.

Despite their reassurance and the many positive aspects of Bromine I decided to research further and one fellow green builder pointed out to me that Bromine is an endocrine disruptor. He pointed me to this breast cancer site where they aren’t very kind to Bromine:

Elevated bromide levels have been implicated in every thyroid disease, from simple hypothyroidism to auto-immune diseases to thyroid cancer…Rats fed even the minimal amount of bromine expected to be encountered in the environment underwent goiter-like changes…Technicians exposed to brominated compounds for prolonged periods developed multiple cherry angiomas on the trunk and extremities…The psychiatry literature abounds with cases of elevated bromide levels being implicated in mental conditions from depression to schizophrenia…Potassium bromate, a bread additive, is known to cause renal damage and permanent deafness in animals and man…The ability of bromate to cause cancer, especially kidney cancer, is a significant health concern…

Etc. Etc.

So what is a Brooklyn green contractor to do if we want to lessen the amount of toxins our clients come in contact with? Clearly gray water that goes putrid isn’t good either. So is it a trade off? Chlorine is better than putrid water?

Like everything in life I think the solution lies in the design. If you are faced with two undesirable options, in this case putrid water vs. chemicals, then maybe changing the paradigm altogether is the solution.

In the case of gray water I think the solution lies in removing the elements that create the putrid water in the first place.

Does this mean not treating the water at all and not storing it and/or having a high turnover of gray water in the container? How does this effect the use of gray water for watering gardens if you don’t have it in a tank? It means building an irrigation system that won’t clog…another challenge. But maybe a better one than trying to decide which chemical to use.

The search goes on for the perfect gray water system in a Brooklyn brownstone. It is an important search and one we are making progress in. We have three brownstones we are designing gray water systems for right now, and luckily for us the clients are forgiving of the fact that they are part of an ongoing search for improvement.