Which Type of Backflow Preventer Is Best for My Property or Application?

If you’re choosing a backflow preventer in Los Angeles, the stakes are high: the right device protects your drinking water from contamination and keeps you compliant with local regulations.

At Atlas Backflow Services, we simplify the decision. Below, we explain the major device types, when to use each, and what our Backflow Testing Los Angeles experts recommend for common residential, commercial, irrigation, and fire system setups.

Quick Answer: Match Your Application to the Right Device

Use this at-a-glance guide to narrow your choice. For specific site conditions, our Backflow Testing Los Angeles experts recommend a short consultation to confirm code compliance and placement.

• Residential hose bibs/garden spigots: Atmospheric or hose-bib vacuum breaker (AVB/HBVB).

  • Why: Prevents backsiphonage at a single outlet.

• Standard landscape irrigation (no fertilizers/chemicals): Pressure Vacuum Breaker (PVB) or Spill-Resistant PVB (SVB).

  • Why: Cost-effective for irrigation and allowed in many LA installations.

• Irrigation with fertilizer/chemicals, or drip with fertigation: Reduced Pressure Principle Assembly (RPZ).

  • Why: High hazard protection for both backsiphonage and backpressure.

• Whole-building domestic service (low hazard) where allowed: Double Check Valve Assembly (DCVA).

  • Why: Low hazard protection; confirm with LADWP before choosing.

• Commercial kitchens, breweries, labs, medical/dental, car washes, salons: RPZ.

  • Why: High hazard fluids are present; RPZ is typically required.

• Soda/carbonated beverage machines: ASSE 1022 backflow device (carbonator backflow preventer) or RPZ as specified.

  • Why: Protects against carbonic acid contamination.

• Fire sprinklers (no additives/antifreeze): Double Check Detector Assembly (DCDA).

  • Why: Low hazard when no chemicals are present.

• Fire sprinklers with antifreeze, foam, or chemicals: Reduced Pressure Detector Assembly (RPDA).

  • Why: High hazard protection for treated systems.

• Highest protection at a single point (e.g., lab faucet, commercial equipment): Air gap (physical separation).

  • Why: Maximum contamination prevention; no moving parts.

When in doubt, our Backflow Testing Los Angeles experts recommend opting for the device that satisfies the highest plausible hazard level and your water purveyor’s rules—often the Los Angeles Department of Water and Power (LADWP) Cross-Connection Control program.

Backflow Basics: What You’re Protecting Against

• Backsiphonage: Negative pressure pulls non-potable water back into the potable line (e.g., a water main break).

• Backpressure: A downstream pump or thermal expansion pushes contaminants backward into the potable line.

Different devices manage one or both risks. The higher the contamination risk (chemicals, biologicals, industrial fluids), the stronger the device you need.

The Main Device Types Explained

• AVB/HBVB (Atmospheric/Hose-Bib Vacuum Breaker):

  • Protects against backsiphonage only.

  • Not rated for continuous pressure.

  • Common for hose bibs and single outlets.

• PVB (Pressure Vacuum Breaker) and SVB (Spill-Resistant PVB):

  • Protect against backsiphonage only.

  • Suitable for pressurized irrigation systems placed above the highest downstream outlet.

  • SVB helps minimize nuisance spillage indoors or near sensitive areas.

  • Our Backflow Testing Los Angeles recommend PVB/SVB for typical LA landscaping without chemicals.

• DCVA (Double Check Valve Assembly):

  • Protects against backsiphonage and backpressure for low hazard applications.

  • Compact and often allowed on domestic services or certain fire lines without additives.

  • Many jurisdictions restrict DCVAs on higher-risk uses; always verify with LADWP or your water purveyor.

• RPZ (Reduced Pressure Principle Assembly):

  • Protects against backsiphonage and backpressure for high hazard situations.

  • Has a relief valve that discharges water—requires a safe drain and clearances.

  • Preferred for irrigation with fertilizers, commercial kitchens, labs, medical, industrial, and any process fluids.

  • Our Backflow Testing Los Angeles recommend RPZs whenever chemicals or high-hazard fluids are in play.

• Detector Assemblies (DCDA/RPDA):

  • DCDA for low hazard fire lines; RPDA for high hazard (antifreeze, foam).

  • Include a metered bypass to detect unauthorized usage.

  • Our Backflow Testing Los Angeles recommend verifying fire authority and LADWP requirements before selection.

• Air Gap:

  • A physical separation between potable outlet and receiving vessel.

  • Highest level of protection; zero moving parts; may not be feasible for every layout.

How to Choose: 6 Key Factors

1. Hazard classification: High hazard (chemicals, biologicals, process water) needs RPZ/air gap. Low hazard may allow DCVA/PVB.

2. Hydraulic conditions: If backpressure is possible, avoid vacuum-breaker-only options; consider DCVA or RPZ.

3. Continuous pressure: AVBs cannot remain under continuous pressure. PVB, SVB, DCVA, and RPZ can.

4. Location and drainage: RPZs discharge by design; plan for a drain and required clearances.

5. Elevation and orientation: Some devices must be installed above all downstream piping and oriented vertically (e.g., PVB, AVB).

6. Local code and purveyor rules: LADWP and California Plumbing Code govern device type, location, and annual testing. Our Backflow Testing Los Angeles recommend confirming with Atlas Backflow Services before purchase.

Los Angeles Compliance Notes

• Annual testing is required for most testable assemblies (PVB/SVB, DCVA, RPZ, DCDA/RPDA).

• Devices must be USC Foundation for Cross-Connection Control and Hydraulic Research (FCCCHR) approved and installed per listing.

• LADWP may require permits, backflow test submittals, and specific containment placement at the service connection.

Atlas Backflow Services can handle device selection, permitting guidance, installation coordination, and annual testing—including digital test reports accepted by local agencies. When regulations are unclear, our Backflow Testing Los Angeles experts recommend letting us verify the purveyor’s current requirements on your behalf.

Cost, Maintenance, and Downtime

• Upfront cost: AVB/HBVB <$100; PVB/SVB ~$200–$600; DCVA ~$300–$900; RPZ ~$500–$1,500+; detector assemblies higher depending on size.

• Testing and service: Annual testing and periodic rebuilds keep devices compliant. RPZs may have higher service needs due to the relief valve.

• Placement tips:

  • Keep devices accessible for testing (clearance required).

  • Protect from flooding/submergence.

  • For RPZs indoors, provide adequate drainage to handle relief discharge.

Our Backflow Testing Los Angeles recommend scheduling testing 30–45 days before your due date to avoid violations and water service notices.

Common Scenarios We See in LA

• Home with simple sprinklers: PVB outdoors above the highest sprinkler head.

• Home with fertilizer injection: RPZ on the irrigation main with protected drainage.

• Restaurant/commercial kitchen: RPZ on the dedicated line serving equipment; ASSE 1022 on beverage carbonators.

• Commercial building domestic service: DCVA or RPZ depending on hazard classification and water purveyor policy.

• Warehouse with fire sprinklers (no additives): DCDA. With antifreeze: RPDA.

• Medical/dental suites or labs: RPZ or air gaps for fixtures and equipment with chemical/biological exposure.

For each, our Backflow Testing Los Angeles experts recommend confirming device size, orientation, and installation clearances prior to ordering.

FAQ

• RPZ vs. DCVA—which is safer?

  
  

  RPZ. It protects against both backpressure and backsiphonage in high-hazard scenarios and vents contaminated water via a relief valve.

• PVB or SVB for irrigation?

  
  

  SVB reduces nuisance spillage and is preferred near walkways or walls. Our Backflow Testing Los Angeles recommend SVB when aesthetics or splash control matters.

• Do I really need annual testing in LA?

  
  

  Yes. Most testable assemblies require annual testing and documentation to your water purveyor (often LADWP).

• Can I install an RPZ indoors?

  
  

  Yes, if you provide adequate drainage and meet clearance requirements. Many choose indoor RPZs to reduce tampering and UV exposure.

Work With Atlas Backflow Services

Choosing the right device is about protecting health and staying compliant. Atlas Backflow Services makes it easy: we evaluate your system, recommend the right assembly, install or coordinate installation, and handle your annual tests and reports.

If you’re unsure which device you need, our Backflow Testing Los Angeles experts recommend a quick site review to ensure you select the safest, code-compliant option.