Water can be heavily impacted by residential construction. Site clearing and grading often cause erosion and polluted runoff. Urban and suburban development decreases the percentage of permeable surfaces, reducing the ability of the land to absorb and filter incoming rain and pollution. And, as population and housing developments expand, there is demand for more water.
Water Quality Impacts
- In 2000, over 40% of the nations’ rivers, lakes and estuaries assessed by states and tribes were found to be impaired.
- Nonpoint sources of suspended solids contribute approximately 95% of the average daily loading of sediments to receiving waters in the U.S.
- Residential land uses have the highest “Event Mean Concentrations” of pollutants in stormwater runoff.
Water Quantity Considerations
- The average American used 5 to 10 gallons of water a day in 1900. By 2000 individual use was estimated at between 50 and 100 gallons a day, and even more if agricultural and industrial uses are determined on a per capita basis. Much of the increase is due to modern conveniences of indoor plumbing (washing machines, toilets, dishwashers, etc.) and exterior landscaping demands. Source: National Wildlife Federation
- Typical household water use in the 21st century includes the following:
- Potable Uses-Food, Drinking, etc (9%)
- Laundry and Dishwashing (16%)
- Toilet Use (19%)
- Shower and Bathing Use (20%)
- Lawn and Garden Use (36%) Source: Green Builder Sourcebook
Reasons to Change
With almost 1,600,000 residential construction projects a year, many impacts can endanger the quality of water and set the stage reduce the quantity of water. Major impacts from residential construction and home use include degradation of water quality and the large amount of water used for lawns and gardens. Another is wastewater. Research indicates that a typical household wastes between 8000 and 10,000 gallons of water a year while waiting for hot water to arrive at the tap. Impacts to water quality and quantity can be reduced through environmental design and construction measures.
Some studies suggest that local drought is caused, or at least made more severe, by sprawl. Consequently, financial and environmental benefits result from designing and building homes with water protection and conservation in mind. They include:
- Avoid National Pollutant Discharge Elimination System (NPDES) penalties
- Reduced material and labor costs by minimizing plumbing and land clearing activities
- Increase marketing appeal
- Lessen strain on municipal services while improving community relations, (this may save money in communities that charge for community service impacts)
- Enhanced stability of groundwater and municipal water sources
- Lower sewage bills or increased life of septic system
- Potentially lower-maintenance landscaping
- Increase energy-efficiency, since water conservation design often reduces energy use as well, e.g. shorter pump run time, shorter water heating time, etc.
- Lower water bills
- Enhanced recreational and economic opportunities in the community
P2 in Action: Site Preparation and Construction Activities
Protecting soil structure and natural vegetation are among the best ways to protect water quality and quantity. Using materials and techniques that enable water to flow naturally above and below the surface without adding pollutants provide the most benefits.
- Design and construct building with minimal impact on site topography and natural drainage ways; disturb only areas needed to install foundations and roadways. Minimize driving on mud.
- Insure that existing (site or neighbors) and new wells are protected (cased, sealed or grouted) from drainage and contamination.
- Design terrain to drain away from wellhead.
- Install anti-backsiphoning valves between well and water pipes.
- Contact the local building or planning department for sewer hookup and the county or state Health Department for septic tank or drainfield installation.
- Maintain a naturally vegetated buffer next to streams, lakes, ponds and wetlands.
- Replace topsoil removed during construction; replant exposed areas as soon as practical.
- Maximize permeable materials for driveways, walkways and porches.
- Use silt fencing or biofiltration (permeable bags filled with chips, compost or bales of straw) to control erosion during construction.
- Designate appropriate locations for washing vehicles and equipment – away from surface waters, storm drains and slopes that could erode, at carwash or at builders’ shop with a sump.
- Sweep surfaces rather than spraying with water; dispose of sweepings in trash instead of down drains.
- Immediately repair all equipment and vehicle leaks.
- Use biodegradable detergents and chemicals; minimize the amount used.
P2 in Action: Indoor Water Conservation
While virtually all water used indoors returns to a system and is reused, domestic indoor demands cost a lot of money because of the infrastructure necessary to deliver it. Conservation, and the suggestions below, can substantionally reduce water demand, extend life of pumps, appliances, and fixtures, and lower costs.
- Strategically place water heater close to point of use (reduces materials and hot water waiting period), install on demand water heater, or an on demand recirculating pump that keeps hot water at the tap.
- Buy high quality fixtures with replaceable parts.
- Capture greywater for toilet and irrigation; divert cool wastewater from showers (prior to hot water arrival) for use in toilets.
- Consider air assisted or compost toilet.
- Choose low-flow equipment for toilet, shower, faucet.
- Choose water efficient appliances and equipment.
P2 in Action: Outdoor Water Conservation
Contentious landscaping can compliment a well-planned lawn. Native, or non-invasive exotic, plants adapted to the region can provide suitable ground cover. They will keep soil in place, reduce the amount of pollen in the air, help water percolate underground, and minimize overall maintenance, including watering. Careful attention to plant selection and watering systems will protect ground and surface water, as well.
- Direct runoff from roof toward landscaping and away from foundation rather than down storm drains (reduces water use as well as storm water and pollutant runoff).
- Maintain and replant hardy, native trees and shrubs; reduce lawn coverage; xeriscape for greatest drought-resistance.
- Remove non-native and nuisance plants without use of herbicides.
- Design a rooftop garden.
- Install a zoned irrigation system, including a rain sensor shut off.