A cistern is a sealed tank for storing water, often for flushing toilets or for rainwater harvesting. Alternatives range from simple buckets to sophisticated whole-house systems, each with pros and cons depending on your needs and water availability. This guide helps you choose the right water storage solution.
As a homeowner, you’ve probably heard terms like “cistern” and wondered what they really mean, especially when it comes to managing water. It’s easy to feel a bit lost when discussing water storage, but don’t worry! This guide is here to clear up the confusion between a cistern and its alternatives.
We’ll break down exactly what a cistern is and explore the many other ways you can store water for different household needs. Think of it as your friendly roadmap to understanding water storage so you can make informed decisions for your home. Let’s dive in and make water management simple!
Understanding the Core: What is a Cistern?
At its heart, a cistern is a special kind of container designed for holding a supply of water. The key characteristic of a cistern is that it’s typically an enclosed or sealed tank. This design helps keep stored water clean and protected from contaminants like dirt, debris, and sunlight, which could otherwise encourage algae growth.
Historically, cisterns were crucial for collecting and storing rainwater, especially in areas where a consistent water supply from wells or municipal sources was unreliable or nonexistent. They function as a reservoir, holding water for later use. Modern cisterns are often used for specific purposes, like supplying water for toilets, washing machines, or for emergency water reserves.
Key Features of a Cistern:
- Sealed Design: Protects water quality and prevents evaporation.
- Storage Capacity: Can range from small tanks to very large underground structures.
- Water Source: Can be filled from rainwater harvesting systems, municipal supply, or wells.
- Purpose-Driven: Often linked to specific appliances or backup water needs.
Cistern Materials and Types:
Cisterns come in various materials, each with advantages and disadvantages:
- Plastic (Polyethylene): Lightweight, relatively inexpensive, and resistant to corrosion. Common for above-ground and smaller underground systems.
- Concrete: Durable, long-lasting, and can be built to large sizes, often underground. Requires professional installation.
- Fiberglass: Strong, corrosion-resistant, and can be used for both above-ground and underground applications.
- Metal (Steel or Galvanized Iron): Strong and durable, but can be prone to rust if not properly coated.
Beyond the Cistern: Exploring Water Storage Alternatives
While a cistern is a specific type of sealed water storage tank, there are many other ways to store water, depending on your needs, space, and budget. These alternatives can range from very simple solutions for immediate, small-scale use to more complex systems designed for significant water reserves.
Understanding these options is vital for choosing the right approach for your home. Whether you’re preparing for emergencies, looking to conserve water, or need a supply for a specific project, there’s likely an alternative that fits the bill. Let’s look at some common alternatives to a traditional cistern.
1. Rain Barrels
For many homeowners, a rain barrel is the most accessible and simplest form of rainwater harvesting and storage. These are typically large drums or barrels that are placed under downspouts to collect rainwater that flows off your roof.
How they work: When it rains, water is directed from the roof through your gutters and downspouts directly into the rain barrel. The barrels usually have a spigot at the bottom for drawing water, and a screen at the top to prevent debris and insects from entering. They are ideal for garden watering and other non-potable uses.
Pros:
- Affordable: Relatively inexpensive to purchase or even make yourself.
- Easy to Install: Usually require minimal setup.
- Eco-Friendly: Encourages water conservation by using free rainwater.
- Reduces Stormwater Runoff: Helps prevent erosion and water pollution.
Cons:
- Limited Capacity: Typically hold only 50-100 gallons, which might not be enough for extensive use.
- Sunlight Exposure: Can promote algae growth if made of translucent material and not kept clean.
- Water Quality: Not generally suitable for drinking without further purification.
- Freezing Risk: Must be drained in winter to prevent damage.
2. Above-Ground Water Tanks
These are similar to cisterns in that they are designed for water storage, but they are typically placed above ground. They come in a wide range of sizes and materials, often used for larger rainwater harvesting systems, livestock water, or as backup water supplies.
How they work: Water is collected from various sources (roof, well, municipal line) and pumped or directed into the tank. They can be connected to your home’s plumbing, but often serve as a standalone source for irrigation or non-potable uses. Materials include polyethylene, fiberglass, and coated steel.
Pros:
- Accessible for Maintenance: Easier to inspect and clean than underground tanks.
- Variety of Sizes: Available in capacities from a few hundred to thousands of gallons.
- Installation Simplicity: Generally easier and cheaper to install than underground systems.
- Can be connected to pumps: For distribution to various uses.
Cons:
- Aesthetics: Can be visually unappealing in a yard.
- Temperature Sensitivity: Water temperature fluctuates more with ambient conditions.
- Wind and Seismic Concerns: May require special anchoring in some areas.
- Space Requirement: Can take up significant yard space.
3. Underground Water Tanks (Similar to Cisterns)
While a cistern is a specific type of underground or sealed tank, the term “underground water tank” is broader. These tanks are buried beneath the ground, offering a discreet and often large-scale solution for water storage. They are excellent for collecting and storing large volumes of rainwater or well water.
How they work: Similar to cisterns, they collect water from a source and hold it. The advantage of being underground is that the earth helps regulate water temperature, keeping it cooler in summer and warmer in winter, and it saves valuable yard space. They are often integrated with pumps to distribute the stored water.
Pros:
- Space Saving: Frees up above-ground space in your yard.
- Temperature Regulation: Earth’s insulation keeps water temperature more stable.
- Aesthetics: Visually unobtrusive.
- Protection: Offers excellent protection from external damage and UV degradation.
- Larger Capacities: Can be installed to hold significant amounts of water.
Cons:
- Installation Cost: Excavation and installation are more complex and expensive.
- Maintenance Access: Can be more difficult to access for cleaning and repairs.
- Potential for Leaks: If not installed correctly, leaks can be harder to detect and fix.
- Hydrostatic Pressure: Must be properly engineered to withstand ground and water pressure.
4. Water Bladders and Flexible Tanks
These are non-rigid, flexible containers made from durable materials like PVC or polyurethane. They are often used for temporary water storage, in tight spaces, or as a more portable solution where traditional tanks aren’t feasible.
How they work: Water is pumped into the bladder, which expands to fill the available space. They are great for use under decks, in crawl spaces, or even temporarily in a garage. They are often used for emergency water storage.
Pros:
- Space-Efficient: Can conform to irregular spaces.
- Installation Ease: Relatively simple to deploy and fill.
- Cost-Effective: Often cheaper than rigid tanks for equivalent capacity.
- Temporary Solution: Good for short-term needs or when permanent installation isn’t desired.
Cons:
- Durability Concerns: Can be more susceptible to punctures or degradation over time compared to rigid tanks.
- UV Sensitivity: Most are not designed for prolonged direct sun exposure.
- Water Quality: May require more diligent cleaning to maintain water purity.
- Not aesthetically pleasing: Often not desirable for visible areas.
5. Emergency Water Storage Containers
These are typically smaller, portable containers specifically designed for storing potable water for emergencies. They range from individual bottles to larger multi-gallon jugs and sturdy buckets with lids.
How they work: You fill them with treated tap water and store them in a cool, dark place. They are intended for short-term use during natural disasters or utility outages. Some are designed to be easily transported.
Pros:
- Convenience: Easy to store and access in a hurry.
- Portability: Many are designed to be carried or moved easily.
- Affordability: Individual containers are low-cost.
- Potable Water: Designed for safe drinking water.
Cons:
- Very Limited Capacity: Only suitable for a few days’ supply for a small number of people.
- Storage Space: Larger quantities require significant storage room.
- Rotation Needed: Water and containers need to be periodically refreshed (usually every 6-12 months) to ensure quality.
Comparing Cisterns and Their Alternatives
Choosing the right water storage solution depends heavily on your specific needs. Here’s a look at how cisterns stack up against some of their common alternatives based on key factors:
| Feature/Type | Cistern (Sealed Tank) | Rain Barrel | Above-Ground Tank | Underground Tank | Water Bladder | Emergency Containers |
|---|---|---|---|---|---|---|
| Primary Use | Toilet flushing, backup water, whole-house (large systems) | Garden watering, small-scale outdoor use | Irrigation, livestock, backup water, rainwater harvesting | Large-scale rainwater harvesting, whole-house backup | Temporary storage, irregular spaces, emergency reserve | Short-term emergency drinking water |
| Capacity Range | 100s to 10,000+ gallons | 50-100 gallons | 100s to 10,000+ gallons | 1,000s to 100,000+ gallons | 100s to thousands of gallons | 1 gallon to 55 gallons |
| Installation Complexity | Moderate to High (depending on size/type) | Very Low | Low to Moderate | High (requires excavation) | Low | None |
| Cost (Initial) | Moderate to Very High | Low | Moderate to High | Very High | Low to Moderate | Low |
| Water Quality Protection | Excellent (sealed) | Fair (can get debris/algae) | Good (depends on material/lid) | Excellent (sealed, stable temp) | Good (protects from light/debris) | Excellent (food-grade, sealed) |
| Space Requirement | Moderate (above/below ground) | Minimal footprint | Significant footprint | Minimal above ground, requires excavation | Conforms to space, can hide | Requires storage space |
| Durability | High | Moderate | High | Very High | Moderate (can puncture) | High for intended use |
Essential Considerations When Choosing Your Water Storage
Before you decide on a cistern or an alternative, there are several crucial factors to consider. Making an informed choice will save you time, money, and potential headaches down the line.
1. Your Water Needs
This is the most important question. Are you storing water for:
- Toilet Flushing? This typically requires a dedicated tank, often a cistern, connected to the toilet’s water supply.
- Emergency Preparedness? For short-term survival during outages, portable containers or smaller bladders are suitable.
- Outdoor Watering (Gardening/Lawn)? Rain barrels or larger above-ground tanks are great options.
- Whole-House Backup? For extended periods without municipal water, a large underground tank or robust above-ground system would be necessary.
- Specific Uses (e.g., washing machine, irrigation)? You might use dedicated tanks or harvest rainwater.
2. Water Source
Where will the water come from?
- Rainwater Harvesting: Connect gutters and downspouts to your storage system. This is a primary driver for using cisterns, above-ground tanks, and rain barrels.
- Well Water: If you have a well, you might store water to equalize pressure or have a reserve.
- Municipal Water Supply: In some areas, it’s permissible to fill a dedicated storage tank from the municipal line as a backup. Always check local regulations.
3. Available Space
Measure the area you have. Do you have ample yard space for large above-ground tanks? Is there a suitable location for a substantial underground installation? Or do you need a solution that fits into a tight spot, like a narrow side yard or under a deck?
4. Budget
Costs vary dramatically. Rain barrels are the cheapest, while large, professionally installed underground cisterns can cost tens of thousands of dollars. Consider not only the purchase price but also installation, plumbing, and potential ongoing maintenance costs.
5. Local Regulations and Permits
This is critically important. In many municipalities, there are specific rules about water storage systems, especially those connected to potable water supplies or for rainwater harvesting that may infiltrate into groundwater. Always check with your local building department or environmental agency.
For example, some areas have restrictions on connecting rainwater harvesting systems directly to indoor plumbing for anything other than toilet flushing, and may require specific air gaps or backflow preventers. The U.S. Environmental Protection Agency (EPA) offers guidance on water quality and conservation practices, which often tie into local regulations.1
6. Maintenance Requirements
All water storage systems require some level of maintenance to ensure water quality and system longevity. Think about how much upkeep you’re willing to do. Cleaning, inspection, and potential repairs are all part of owning a water storage solution.
Step-by-Step Guide: Installing a Basic Rainwater Harvesting System (with a Rain Barrel)
For beginners, setting up a simple rain barrel system is a fantastic way to start managing water and understand the basics of harvesting. It’s achievable, affordable, and has clear benefits.
Tools and Materials You’ll Likely Need:
- Rain barrel (with overflow hose, screen lid)
- Downspout diverter kit or elbow connector
- Flexible overflow hose
- Level
- Drill with appropriate bits
- Sealant (suitable for outdoor use)
- Sturdy, level base (e.g., concrete pavers, concrete blocks)
- Gloves and safety glasses
Installation Steps:
- Choose the Location: Select a downspout from your roof that ideally leads to a sunny spot (for heat to kill some bacteria and algae, though some prefer shade to reduce algae). Ensure the ground is level and can support the weight of a full barrel (a 55-gallon barrel can weigh over 450 lbs when full).
- Prepare the Base: Place your level base (pavers or blocks) in the chosen location. This is crucial to prevent the barrel from tipping or sinking into the ground.
- Modify the Downspout: Follow the instructions for your downspout diverter kit. This usually involves cutting a section out of your existing downspout and inserting the diverter mechanism, which will direct water into the barrel. If not using a diverter, you might simply attach an elbow to direct the spout into the barrel.