With drought gripping much of the country, and the price of water on the rise, it’s become increasingly important to know how much water you use to irrigate your yard as well as how much it costs.

Watering Dos and Don’ts

Water your yard early in the morning and soak the ground thoroughly to a depth of three inches or more. The general rule of thumb is to provide one inch of water to your lawn per week during dry conditions, but this can vary greatly depending on where you live and the time of year. To see how much water your grass is actually receiving, put a container with straight sides—such as a coffee mug or plastic container—on the ground in the yard while you are watering. Then use a ruler to measure the depth of the water in the container.

Calculating Water Use

To provide your lawn with one inch of water takes a little over half a gallon per square foot (0.623 gallon to be more exact). That means that every 10’x10’ area will require over 62 gallons of water. That doesn’t sound like much until you consider that a 100’ x 100’ lawn uses 6,230 gallons of water every time you turn on the sprinklers!

To calculate the amount of water you use, multiply the width times the length of your yard in feet to get the number of square feet of area. Then multiply that figure by 0.623 to come up with the number of gallons used (or use our calculator below). This assumes that your yard is square or rectangular. For more unusual shapes, you’ll have to dig out your old high school geometry book to come up with the amount of area involved.

Calculating Water Costs

Now that you know how much water you’re using, you can estimate how much it will cost to keep your lawn green. While city water systems usually give separate prices for water and sewer services on your bill, in most cases both are actually based on the number of gallons of water you use. So for every 1,000 gallons of water that comes out of your faucet, you are also charged not only for the water but for 1,000 gallons of sewerage. This holds true regardless of whether it goes down the drain or on your grass.

Many cities will install a separate meter for irrigation purposes that does not include the cost of sewerage. This can save a lot of money, though you will have to pay several hundred dollars to have it hooked up as well as a monthly minimum whether you use it or not.

To calculate the cost of watering your yard, divide the number of gallons used by 1,000 then multiply by the price you pay per 1,000 gallons (see our calculator below). Don’t forget to include the sewer costs unless you have a separate meter.

Here in Mobile, Alabama, it costs $2.00 per 1,000 gallons for water plus $4.26 per 1,000 gallons for sewer, for a total of $6.26 for every 1,000 gallons of water that comes out of the tap. That means that to supply a 100’ x 100’ yard with one inch of water costs over $12.00 if you have a separate meter for irrigation or $39.00 if you don’t. If you water your yard every week during the summer, the cost will add up to close to $50 or $156 a month.

Given the severity of the current drought, water rationing is already taking place in some parts of the country. When supplies run short, lawn irrigation is the first thing to go. If you find the cost of watering your yard too steep—either financially or ecologically—you might consider getting rid of grass altogether and planting drought resistant shrubs and other plants instead. Not only will it help conserve water and save money, but you won’t spend your Saturdays behind the lawn mower either.

While lumber is commonly sold by the piece in building supply stores, wholesalers and hardwood dealers usually price their stock by the board foot. Ask for a dozen two by fours eight feet long at your local sawmill, and you’ll be told that what you really want is 64 board feet of lumber.

It’s not as confusing as it sounds as long as you remember that a board foot is a measure of volume equal to a square foot one inch thick. So a 1” by 12” a foot long and a 2” by 6” of the same length both equal one board foot. Rough lumber measurements in width and thickness are used when calculating board feet even if the lumber has been planed down.

To calculate the number of board feet, use the following formula:

thickness (inches) x width (inches) x length (feet) ÷ 12 = board feet

Below are some common widths and their equivalent in board feet per foot of length:

• 1” x 4” x 1’ = 0.33 bd. ft.
• 1” x 6” x 1’ = 0.50 bd. ft.
• 1” x 8” x 1’ = 0.67 bd. ft.
• 1” x 10” x 1’ = 0.83 bd. ft.
• 1” x 12” x 1’ = 1.0 bd. ft.
• 2” x 4” x 1’ = 0.67 bd. ft.
• 2” x 6” x 1’ = 1.0 bd. ft.
• 2” x 8” x 1’ = 1.33 bd. ft.
• 2” x 10” x 1’ = 1.67 bd. ft.
• 2” x 12” x 1’ = 2.0 bd. ft.

To find the number of board feet, multiply the number above by the length of the board, then multiply the total by the number of boards needed.

While you can do the math with a pencil and paper, it’s a lot easier to use our online board foot calculator:

Heating water is the second largest single user of energy in the home. While we all enjoy a soothing hot shower, rising energy costs—along with their adverse environmental impact—make it a good time to take a closer look at the various options now available.

Types of Water Heaters

• Storage: The most common hot water system used in homes. Water is kept constantly heated in the storage tank by electricity, natural gas, oil, or propane. Hot water is drawn out of the top of the tank when a faucet is turned on and cold water flows in the bottom to replace it.
• Tankless: Also known as demand or instantaneous water heaters. Water is heated instantly by electricity or gas when water flows through it.
• Solar: Water is circulated from the tank through a solar collector where it is heated by the sun. If the water in the tank is not hot enough, a conventional water heater is used to bring it up to the desired temperature.

Decisions, Decisions

So which type of water heater is right for your home? There are several factors to consider including the price of the system and installation, the cost and availability of energy sources, and the energy factor (EF) rating of the water heater.

EF ratings were established by the U.S. Department of Energy to compare the energy efficiency of various products. The EF scale for water heaters runs from a low of 0.5 for gas storage tank heaters to 2.0 for electric heat pump models. The higher the EF, the more efficient the water heater. The EF number takes into account:

• Recovery Efficiency: How efficiently the heat is applied to the water.
• Standby Loss: The percentage of heat loss per hour of the stored water.
• Cycling Loss: The loss of heat as the water circulates through the unit.

Energy Cost Calculator

Most water heaters run on either electricity, natural gas, or propane. Since energy prices can vary widely, fill in the values in the calculator below to compare energy costs in your area. While the actual amount spent will depend on how much hot water you use, the calculator will give a comparison between the various energy sources available. Preset values in the calculator represent average EF rating and energy prices in the U.S. for 2006.

On average in the U.S. in 2006, it cost 1/3 more to heat water with electricity than natural gas. Propane was the most expensive of all at 50% more than gas.

Pros and Cons

Here are some of the advantages and disadvantages of the most common types of water heaters:

Storage Heaters

• Inexpensive and widely available in a variety of sizes.
• Waste 10%-15% of energy through radiant heat loss.
• Can run out of hot water during extended use.
• Life expectancy 10-15 years.
• Average EF rating 0.67.
• Cost $200-$400 plus installation.

Tankless Heaters

• Take up little space and can be mounted inside or on an outside wall.
• Little or no standby energy loss.
• Use 20% to 30% less energy than comparable storage tank models.
• Hot water flow rate is limited by the size of the unit.
• Can be expensive and costly to install.
• Life expectancy 20 or more years
• Average EF rating 0.75.
• Whole house tankless systems cost from $600-$1000 or more plus installation.

Solar Heaters

• Low to no energy cost.
• Savings can pay for the unit in 8-12 years.
• Requires the collector to be in full sun throughout the year.
• Expensive and costly to install.
• Usually use a conventional water heater for backup.
• Life expectancy 20 or more years.
• Do-it-yourself kits are available for $2,000. Professionally installed systems run $5,000-$7,000.

Going Tankless

Available in both electric and gas models, tankless water heaters are considered more energy efficient than storage tanks but cost substantially more to buy and install. Gas tankless water heaters often require a larger gas line and modifications to the vent pipe while large tankless electric models may draw more current than the house is designed to handle. The extra expense may be offset somewhat by a $300 federal tax credit for gas models with a minimum 0.80 EF rating that are purchased in 2006 or 2007.

Small single use electric units are less expensive and can be mounted under a sink. They come in handy if you have a half bath or kitchen sink located away from the main hot water heater. Rather than wasting water waiting for it to get hot, the tankless heater will supply hot water right away.

Be sure and check the recommended flow rate on tankless water heaters to see if it is enough to meet your needs. While they won’t run out of hot water like traditional storage tanks, multiple users can exceed the flow rate and cause the water temperature to drop.

Here Comes the Sun

The collector on a solar water heater needs to be located where it will receive full sunlight throughout the day. For maximum efficiency it should face south and be tilted at an angle equal to the latitude. Solar water heaters will work at a lower slant or when facing southeast or southwest, though not as effectively.

Solar hot water heaters use either natural circulation or a pump to move water between the collector and storage tank. Some systems circulate the water from the storage tank through the collector while others use a heat exchanger in the tank to keep the fluid in the collector separate from the water in the tank.

Though expensive to buy and install, solar water heaters are eligible for up to a $2,000 federal tax credit through 2008.

Energy Efficiency Payback

To find out how long it would take an energy efficient system to earn back its added expense, divide the additional cost of the energy efficient system by the yearly savings in energy. The answer is the number of years it would take the energy efficient system to pay for itself.

$ added cost ÷ $ saved in energy a year = years to payback

Online Resources

• US Department of Energy: Selecting a New Water Heater
• American Council for an Energy Efficient Economy: Water Heating

Tankless Systems

• Paloma Tankless Water Heaters
• Bosch Water Heater
• Tagaki Industrial Co.

Solar Systems

• Solar Rating and Certification Corporation
• Solar Smart Water Heating Systems
• Hot2o DIY Solar Hot Water Heater