Designing Rainwater Harvesting Systems: Integrating Rainwater into Building Systems

Preface ix

Acknowledgments xiii

1 The Importance of Rainwater Harvesting 1

Water Capital 2

A Brief History of Centralized Water Systems 6

New Approach to Centralization—Decentralized Rainwater Systems 9

Examples from Around the World 11

India 11

Germany 13

The United States 16

Policy Issues and Sustainability 20

Water and Energy Savings 20

Response to Drought Conditions 23

Privatization and Relocation 25

Valuing Water Resources 25

History and Early Codes 25

Source 26

Value and Water Rates 27

Return on Investment 28

Challenges, Education, and Paradigm Shifts 34

Stereotypes and Preconceptions 34

Rainwater Technical Standard 34

Water Quality 35

Paradigm Shift 35

Endnotes 37

2 System Planning and Policies 39

Benefits That Drive Rainwater Harvesting Systems 39

Planning a System 40

Step 1: Identifying System Goals 46

Step 2: Codes, Standards, and Guidelines 49

Step 3: Incentive Programs and Rating Systems 63

Step 4: Educating and Involving the Stakeholders in the Design Process 71

Step 5: Putting It All Together 73

Endnotes 76

3 Water for Thirsty Buildings 79

Rainwater: Calculating Collection and Use 79

Step 1: Creating a Water Audit 82

Step 2: Calculating Annual Rainwater Supply 83

Step 3: Calculating Demand 89

Building Sectors, Sizes, and Demands 91

Small Office 91

Schools in Different Climate Regions 93

Step 4: Cistern Sizing 100

Alternative Water Sources 103

Other Wastewater and Recirculated Water 103

Plumbing Design and The Myth of Unlimited Water Supply 108

Thoughtful Planning Brings Success 111

Endnotes 113

4 System Elements 115

Integrated Approach 115

Opportunities for an Integrated Approach 117

1. Collection/Catchment Surface (Roof or Other) 118

2. Conveyance (Gutters and Downspouts) 123

Dry Conveyance versus Wet Conveyance 124

Sizing and Numbers 125

Aesthetics/Functions/Budget 126

Conveyance Functions 128

Conveyance Budget 128

3. Prestorage Filtration and Debris Exclusion 128

Prestorage Filter Types and Applications 128

Downspout Filters 130

Basket Filter 131

Centrifugal Filters 132

Cascading Debris Excluders 133

Prestorage Filtration Devises 134

Filter Sizes 134

How Components Help Merge the Goals of Rainwater and Stormwater 134

4. Storage 135

Aboveground Tanks 138

Belowground Tanks 139

Factors to Consider 140

5. Distribution 141

1. Pressurization 141

2. Filtration 141

3. Disinfection 143

4. Contoller 143

5. Automatic Protected Bypass 144

6. Makeup Supply 145

Integration, Thoughtful Planning, and Continuing Education

Are the Keys to Success 147

Endnotes 149

5 Maintenance and Safety 151

Water Quality of a Rainwater System 151

Sources of Pollutants 155

Fate and Transport of Pollutants in a Rainwater Harvesting System 158

Microbial Contamination 162

Addressing Water Quality for Various End Uses 163

First Flush 164

Water Testing Protocols 169

Using a Bypass / Backup Water Supply 170

Maintenance Considerations 174

Case Studies—Cautionary Tales and Pilot Projects for Potable Water Systems 174

Summary of Design Recommendations 177

Conclusion 186

Endnotes 192

6 21st-Century Interviews 195

Stan Abbott 196

John Apostolopoulos 200

Alf Brandt 205

Bob Drew 209

Nicole Holmes 212

Bill Hunt 216

Lutz Johnen 222

Heather Kinkade 227

Kevin Kirsche 230

Billy Kniffen 233

Dennis Lye, PhD 237

Shawn Martin 245

Neal Shapiro 251

David Stooksbury 256

Dave Viola 259

Endnote 261

Appendix A 263

Appendix B 277

Index 283