Water, Water Everywhere....

Never mind saving for a rainy day. How about saving for a dry one?

• Archeological evidence show rainwater capture 4000 years ago

• Ruins of cisterns built as early as 2000 BC are still standing in Israel.

Rainwater

• Renewable, sustainable high quality water source

• It is soft, neutral in pH

• Free from disinfection by-products, salts, minerals, and other natural and man-made contaminants

IS IT SAFE?

Absolutely -providing it is collected, stored and disinfected correctly.

Rainwater Harvesting System

Four main functions:

• catch rainwater from the roof and gutters

• transport the water through the downspouts and pipes

• remove debris and clean the water

• store the water

Rain Harvesting Systems

As simple as

capturing rain

in a barrel

for gardening

from architects, engineers, and filtration/water treatment specialists

Or Complex

Requiring input from

Types of systems

• Full: no other source of water, total house system

• Partial: back up well or city water: gardening, flushing toilets, laundry

• Occasional: seasonal, gardening

Collection Techniques

Above ground outdoor are Simple: – reduce the amount of debris, pollen,

bird droppings or organics from getting into the barrel.

– Protect the barrel/tank from UV

– Control access to mosquitoes

For Indoor Use

More attention and commitment

Debris catchment devices and filtersFirst flush diverterPumps and pipingFilters and disinfectantsMaintenance and seasonal cleaningTesting

How Much Water Do I Need?

Start by looking at your water practices.

Are there ways to conserve water on a daily basis?

Indoor Water Conservation

Average Indoor Water Use–Toilet flushing - 40% –Bathing - 32.5% –Laundry - 17.5% –Cooking / Dishwashing - 10%

Water Saving Appliances

• Water saving appliances pay for themselves in 1 or 2 years because they reduce the size and the capital cost of the cistern (ie. less water needs to be stored).

• Water-saving appliances– Faucet aerators and efficient showerheads– Low water use dishwashers and washing machines– On-demand hot water units– Composting toilets.

Toilets

Low flush toilets lower indoor water use by as much as 15% & pay for themselves in a year.

Toilet Reuse of Grey Water

Summer Outdoor Water Use

• 1 watering can = 3.3 gal. • 3 ft. shrub in hot weather (1 week) = 7 gal. • 18 in. pot in hot weather (1 week) = 1.8

gal. • 40 deck pots – drip water (1 week) = 50

gal • 1 sprinkler full flow (for 1 hour) = 240 gal. • Car washing (1/2 hour) = 120 gal. • Pressure washing (1/2 hour) = 40 gal.

Decision #1

What do you want your system to do?

A few basic considerations before you get started:

–Annual Monthly Rainfall–Catchment Size–Tank Size–Cost

Portland Monthly Average ParticipationJan 07 2.86 Jan 08 3.21 Jan Annual

Average

4.09

Feb .96 Feb 8.06 Feb 3.14

March 3.01 March 5.54 March 4.14

April 8.97 April 4.47 April 4.26

May 2.32 May 1.09 May 3.82

June 3.33 June 3.88 June 3.28

July 4.64 July 3.32

Aug 3.23 Aug 3.05

Sept 3.22 Sept 3.37

Oct 6.37 Oct 4.4

Nov 4.21 Nov 4.72

Dec 3.79 Dec 4.24

Catchment Size

How much rain will my roof collect?

• Measure the perimeter of your roof then calculate the area as if the roof were a flat surface (like a floor plan)  

 

Measure the roof ignoring the angle of the roof.

Length x Width gives us the square footage.

20’ x 50’= 1,000sq. Ft.

Bird’s eye view

50’ long

20’ Wide

Calculate Potential Catchment

Portland annual rainfall: 45.83 in per yr (or 3.82 ft)

Roof Area 20’ X 50’ = 1000 sq ft

3.82’ of rain/yr X 1000 sq ft= 3820 cu.ft.

3820 x .80 = 3056 cubic ft. (assuming an 80 % efficiency of collection)

• 7.5 gallons = one cubic foot

• 3056 cubic ft x 7.5 gal./cubic ft =

22,920 gallons per year

SkyJuice Table

How Much Water Do You Use?

To determine the size of the tank and how much water you will need,

you must calculate how much water your household uses in a day.

Indoor Water Use

• Most homes use 50-60 gallons per person per day.

• Conservation minded households use 35-40 G/P/D and some are as low as 25-30 G/P/D.

To Calculate How much your family uses, here are some of the factors:

Total Number of People in the Home

Bathroom

Showers: Number of showers. length of showers, flow rate (gallon per minute of the shower head)

Baths per week, amount of water in tub

Toilets: Number of time each person flushes, gallons per flush

Faucets: times per day to shave, brush teeth, wash hands and minutes per use

Dishes/Laundry

Dishes: how many dishes do you wash by hand, minutes water run with each wash, times dishes washed by dishwasher, times used per week, gallons per load (15 normal)

Laundry: loads per week, water per load (55 gal normal)

Outside Water Use

Lawn or garden watered times a week, minutes watered

Other uses: wash Car, fill pool, rinse furniture, clean equipment minutes per week

Water Use Calculator

• Found on the web

• Allows you to enter all of your data and gives you the gallons per day used by your family

So, let’s say you conserve water and have 4 members in your family.

 

4 x 30 gal per person = 120 gallons a day for the whole household. 

What size of tank does your family of four need?

Using rainwater as your primary water source, you

need to consider how much of a reserve your household will require.

 

With an average of 3 inches per month, we still need to consider the possibility of a 50 day drought.

120 gallons per day x 50 days of drought

= 6000 gallons

If you want the full home system, the tank needs to be 6,000 gallons.

All indoor use systems share basic components and considerations.

• Roof Material

• Gutters and Downspouts

• Roof Washing

• Storage tank

• Distribution System

• Filtration

• Installation Costs

The Roof

• Non toxic and inert (non leaching.)

This is particularly true of the roof that is subject to the oxidizing affects of sun and air borne pollutants.

Avoid lead flashings around sky lights or plumbing vents.

Water Quality

Water quality varies dependent on:

• Type of roof material

• Climate conditions

• Surrounding environment

Water Quantity

The quantity of rainwater that can be collected is also a function of roof texture.

The smoother the better.

Metal Roof

Most common roofing material used for rain catchment is galvanized metal that has been painted or enameled with a non-toxic material (lead free).

Other surfaces may be used if they do not contain lead, zinc coatings, or copper.

Acceptable roofing also includes slate, reinforced concrete, cement tile, and terracotta tile

Asphalt Shingles• Asphalt shingles

produce less water and are harder to keep clean.

• Beware of the shingles that contain moss inhibitors for bathing and drinking.

Cedar Roofs

Water collected from cedar roofs is acidic for plants and is impractical for indoor use.

Gutters

The most common gutters are one-piece, baked aluminum gutters.

Half-round vinyl is also excellent.

Gutters and downspouts must be lead, zinc, and copper free

Areas where the water can pool collect insects, organic materials and bacteria. Think of a gutter as a river - not a wetlands or swamp.

Gutter Guard

+ Keeps some debris out

- Protects the debris that collects in the gutter from the sanitizing and self cleaning of sun and wind.

Debris Traps

• Clean the water before it enters storage

• A small leaf trap and cleanable pipe systems to catch the larger heavier debris may be all that is required.

Downspouts Anything from non-copper chains to traditional aluminum downspouts can be used to get the water down from the gutters

First FlushAmount of water to flush

depends on: • Roof and gutter slope • Roof material

smoothness • End use • Rain intensity • Airborne pollutants (dust,

smoke, auto exhaust) • Tree debris

Potable System First Flush

Flush the first 0.02 inch of rain.

Or 10.4 gal per 1,000 sq ft of catchment area.

First Flush

The WISY Vortex Underground Filter

• Handles a ton of rainwater• Installed underground• Standard size for roof areas of up to 5000 sq ft.• Small size for roof areas up to 2000 sq. ft.• Self-cleaning filter • Captures over 90% of the rainwater

The WISY Vortex Underground Filter

Water comes in

Water to tank

Overflow and debris outlet

Filter

Ground level

Storage Tank

Where are you putting it:

Aboveground, under ground, in home

Most common residential tanks:

Concrete, PVC, Fiberglass

PVC…above ground

Tank at Jackson Marine Lab University of New Hampshire

Least Expensive

Easy to Install

300-3,000 gallons

Seasonal Use

Dark colors (UV protection)

Gravity flow or pump

Indoor PVC Tanks

• 300-400 gallon• Fits through existing doorways• Can connect multiple tanks• Weight on cellar floor may be an issue

Custom Concrete Tanks

Under the home

Under the deck

Prefab Concrete Tanks

1000 Gal Septic Tank

Remove baffles

Add one opening for water to return to house

Genest Concrete

Concrete Tanks for Potable H20

Solvent-Free Coatings:

• Helps Waterproof the tank

• Environmentally friendly

• No taste or odor

• No leaching• CHEMTHANE 4200PW, Enviroline & AmTec

Fiberglass Tanks

• Underground• Four Season• Safe, long-term storage of potable water• Large capacity• Expensive

WISY Floating Suction Filter

Back Flow Preventer

Fine Gauge Particulate Filter Mesh Float

Ensures water is extracted where it is the cleanest.

Distribution System

Grundfos MQ3 PumpRecommended by Texas Guide to Rainharvesting• Compact, easy to install and operate. • Pressure switch and tank built in • Self priming and water-cooled, low noise level. • User-friendly • auto reset, alarm if dry running or overheating. • Anti-cycling feature prevents the pump from repeatedly starting and

stopping in the event of a dripping tap or a minor leak. • Stops when the tank is dry, and restarts automatically when water is

available again.

Treatment of Rainwater

• Simpler than treating water from wells

• Remove parasites, bacteria, and virus from bird droppings, as well as insects, and wind blown materials that are carried onto the roof.

• Toxins leached from the roofing system can include heavy metals, petroleum products, algae, moulds, and yeast.

Filtration Types

• Chlorination

• Particulate

• Carbon

• UV

• Reverse Osmosis

• Distillation

Chlorination

• Shock chlorination consists of mixing sufficient chlorine-based chemical with the tank water to create a solution containing 200 parts per million (ppm) of chlorine

• Kills algae

Sediment/Particulate Filter

Different micron sizes

Removes:

• Dirt

• Sediment

• Rust Particles

Sediment Filters

Improve

• Water clarity

• Taste

• Odor

Protects plumbing system and

charcoal filters from sediment build-up

Carbon Filter Derived from coconut husk• Easy to Install• Relatively inexpensive• Removes:

– chlorine, chloramine, chlorine disinfection by-products (trihalomethanes - THMs),

– Bad Taste and odors– many organic contaminants – fine sediment

Carbon Filter

• Does not change pH of water

• Pre-treatment for Reverse Osmosis and UV systems

• 0.5 micron carbon block filters remove cysts ( Giardia and Cryptosporidium)

• .01 filter inhibits Viruses

Change filters regularly:Susceptible to mold…

Filter collects “garbage” in your water

Taste change means change the filter…

Reduced efficiency the longer they are used

Minerals

• Minerals in solution can still permeate a charcoal filter.

• Are essential for health.

Ultraviolet Light Purification

Non-chemical approach

No harmful bi-products or chemicals Does not alter the taste, pH or other properties of

the water

Not harmful to your plumbing or septic system

Removes some volatile organic chemicals,

Low Maintenance

Easy and cost effective to install and maintain

UV SystemStage 1

.5 micron carbon block

Removes Sediment

Reduces chlorine, herbicides, pesticides, benzene

Removes odor and taste

Removes Cysts (cryptosporidium, giardia)

Stage 2: UV Disinfectant

– Bacteria: E-coli and fecal

Coliform Viruses

– Viruses

– Mold spores

– Algae

– Yeast

– Protazoa

Reverse Osmosis Systems

• Ultrafiltration: Extremely fine membrane allow water molecules, but not larger compounds.

•The contaminated water is put on one side of the membrane and pressure is applied to stop, and then reverse, the osmotic process. Takes a lot of pressure, is fairly slow, but results is extremely finely filtered water.

Reverse Osmosis

• Reduces Calcium Deposits

• Improves Taste, Odor, and Quality of Water

• Removes Existing Scale

• Reduces the Need for Household Chemicals

• Requires No Chemical or Salt Regeneration

Reverse Osmosis

• Requires high water pressure

• Water pressurization system may be required.

• Plumbing work necessary

• More costly replacement membranes

• Removes Minerals

Water Distillers

• There is a growing awareness of distilled water's effects on the balance of minerals in the body, plus the acidic result that a typical distiller creates.

• Dissolved minerals in the water are more natural than pure water, and serve an important function in supporting the body's immune system and metabolism.

• Water without minerals can be a health problem. According to the U.S. EPA, "Distilled water (which is identical to RO water ~Ed), being essentially mineral-free.

Installation Costs

• Roof Material

• Excavation

• Tank

• Plumber