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Water conservation has become a priority for homeowners looking to reduce their environmental impact and lower utility bills. One innovative solution is using graywater in toilet tanks. This method recycles water from sinks to flush toilets, significantly reducing household water consumption.
In the video above, This Old House plumbing and heating expert Richard Trethewey explains two efficient ways to implement this water-saving technique in your home. We’re also providing tips and recommendations to keep your graywater system running efficiently.
What Are Graywater Systems?
Graywater is lightly used water from household activities such as handwashing, laundry, and bathing.
Graywater systems capture this water from sinks, showers, and washing machines and repurpose it for non-potable uses, such as flushing toilets. Graywater doesn’t include water from toilets or kitchen sinks, called blackwater, due to potential contamination from waste or grease.
By using graywater, homeowners can save water, cut utility bills, and contribute to a more sustainable lifestyle.
Benefits of Using Graywater in Toilet Tanks
Using graywater in toilet tanks offers several advantages:
- Water conservation: Toilets account for a significant portion of household water usage. By using graywater instead of fresh water, you can conserve a considerable amount of water.
- Lower utility bills: Reducing the amount of freshwater used for flushing can decrease your water and sewage costs noticeably. This is especially true in areas with high water rates or drought restrictions.
- Environmental impact: Using graywater reduces the demand on local water resources. This helps communities in regions prone to drought or water shortages.
- Sustainable living: Integrating graywater systems into your household promotes eco-friendly practices and helps move toward a more sustainable lifestyle. It reflects a commitment to reducing waste and conserving valuable resources.
Combination Toilet/Sink Fixtures
Installing a combination toilet/sink fixture is a practical way to integrate a graywater system into your home. This fixture combines a sink and toilet into one unit, allowing you to use the water from handwashing to fill the toilet tank.
Installation Process
Installing a combination toilet/sink fixture is similar to replacing a standard toilet. Here’s an overview of the process:
- Start by turning off the water at the shut-off valve located behind the toilet.
- Flush the toilet and hold down the handle to drain the toilet tank.
- Sop up the remaining water from the toilet bowl with a large sponge.
- Use a wrench to disconnect the water supply line from the underside of the toilet tank.
- Pull off the plastic caps concealing the closet nuts on the sides of the toilet base. Remove the nuts with a wrench.
- Rock the toilet back and forth to break its bond with the wax gasket.
- Carefully lift up the toilet and carry it from the bathroom.
- Use a putty knife to scrape any remaining wax from the closet flange (toilet drain).
- Press a new wax gasket onto the closet flange, then set the combination toilet/sink on top of the gasket.
- Push down on the toilet with all your weight to compress the wax gasket. Then, alternately tighten the nuts onto the closet bolts. Repeat until the toilet is fully seated.
- Reconnect the water supply line and turn on the shut-off valve.
Retrofit Sink Kits for Existing Toilets
If you’re not ready to replace your entire toilet, you can install a retrofit sink kit to convert a standard toilet into a water-saving graywater system. This involves placing a small sink on top of the toilet tank, where handwashing water flows directly into the tank. Kits include plumbing connections to divert clean water to the sink and a drain line to channel used water into the tank.
Installation Steps for Retrofit Kits
Installing a retrofit sink kit is a relatively simple process that takes less than five minutes. Here’s how to do it:
- Begin by removing the lid from the top of the toilet tank.
- Remove the refill tube from the toilet.
- Connect the water supply line for the sink to the fill valve inside the toilet.
- Insert the sink’s drain line into the toilet’s discharge tube.
- Set the retrofit sink on top of the toilet tank. If necessary, use the included spacer to adjust the sink to fit the tank’s length.
Key Considerations for Graywater Systems
Before installing a graywater system, take into account the following factors that may influence your plans.
Check Local Regulations
Some areas have specific rules or codes regarding the use of graywater. Consult local building codes to make sure your system complies with regulations, as permits or inspections may be required. Restrictions often apply to how graywater can be used, especially for irrigation.
Verify Water Quality
While graywater is generally safe for flushing toilets, it should come from appropriate sources. Only use graywater from sinks, showers, and laundry that doesn’t include harsh chemicals or potential contaminants. Avoid using water containing harmful bacteria or residues from cleaning products, as these could pose health risks or affect your plumbing.
Graywater System Maintenance and Care
Here are some helpful tips to keep your graywater system working properly.
Regular Maintenance
Graywater systems should have basic filtration to remove debris and soap scum before water is reused. Regularly clean filters and check plumbing connections to keep the system functioning smoothly and prevent unsanitary conditions caused by clogs or dirty components.
Safe Cleaning Products
The cleaning and personal care products you use influence the quality of your graywater. Avoid harsh chemicals, bleaches, and non-biodegradable detergents, which can contaminate the graywater and make it unsuitable for reuse. Opt for biodegradable and eco-friendly cleaning products to keep graywater safe for flushing toilets.
Chemical Buildup
Household cleaning products or personal care items can leave chemical residues in graywater, potentially harming plants if used for irrigation or causing a buildup in the system. Monitor the impact on soil and plants and avoid using graywater that contains unsuitable chemicals.
Leaks and Repairs
Address any leaks or malfunctions quickly to prevent water damage and system failure. You might perform immediate repairs for minor issues like small leaks or clogs, but consult a professional plumber for significant or persistent problems.
Seasonal Upkeep
Seasonal changes can impact your graywater system. In colder climates, insulate pipes and drain excess water to prevent freezing and damage. During warmer months, monitor the system for increased usage and make sure it remains clean and functional to handle the higher volume of graywater effectively.
How To Enhance a Graywater System
If you already use a graywater system, adding the following enhancements can improve its efficiency and effectiveness.
Advanced Graywater Systems
Advanced graywater systems with automated controls simplify water reuse by distributing graywater to toilets, irrigation, or other non-potable uses. Filtration units clean the water, removing particles and keeping plumbing systems in good shape. While these systems have a higher upfront cost, they deliver long-term water savings by reducing waste and optimizing usage.
Tip: Regularly maintain filters and valves to maintain efficient system performance.
Custom Solutions for Unique Needs
You can tailor a custom graywater system to your home’s specific water needs. For instance, households with large landscapes can direct graywater to irrigation, while others may focus on bathroom use. These systems can also be designed to fit seamlessly into your home’s existing plumbing.
Working with a professional guarantees the system complies with local codes and is installed properly. Design your system with flexibility to accommodate future upgrades or changes as your household needs evolve.
Integration With Smart Home Technology
Integrating graywater systems with smart home technology lets homeowners monitor water usage in real time. Apps allow you to track water savings, detect leaks, and adjust remotely. These systems can automatically adjust water flow based on demand, making them ideal for maximizing efficiency with minimal effort. Set up maintenance alerts through your smart system to stay on top of upkeep and prevent issues.
