Watflow DN20 Water Meter 3/4ft NPT - Accurate Gallon Pulse Output

In this review the Watflow DN20 water meter is examined for installers and facility managers who need a robust, accurate cold water flow instrument with pulse output. The single biggest reason to buy is its combination of a corrosion-resistant brass main case and reliable accuracy across a usable flow range, which makes it suitable for garden irrigation, small factory lines, or pulse-based monitoring systems. The review focuses on build, accuracy, installation, and the pulse output feature to show where this meter performs best.

Key Features

• Corrosion resistance: The main cases use an eco-brass alloy and materials selected for resistance to corrosion, which helps ensure long service life in outdoor or industrial settings.
• 3/4' NPT compatibility: Equipped with 3/4' NPT couplings and calibrated in gallons, the meter fits common US plumbing and measurement setups without adapters in many applications.
• Accuracy across flow range: The meter maintains a maximum permissible error of about 1.5% in the normal flow range and about 3% at low flow, which is suitable for monitoring and billing-adjacent uses.
• Pulse output: The built-in pulse output allows straightforward integration with remote counters or data loggers for automated monitoring.
• Serviceable inlet filter: The inlet filter is removable and cleanable without breaking the metrological seal, simplifying maintenance in dirty-water environments.
• Durable design: The single-jet, magnetically driven register and composite body materials provide a simple, serviceable construction for routine use.

Who It's For

The Watflow DN20 is aimed at small industrial users, installers, and homeowners who need a reliable cold water flow meter that reports in gallons and offers pulse output for automated monitoring. It is a practical choice for garden irrigation systems, small factory process lines, and situations where a clear pulse signal is required for remote monitoring.

Those who need certified lead-free construction or a hot-water-specific meter should look elsewhere, since this model is specified as not lead-free and is described as suitable for cold water; for very low-flow precision metering under 0.25 GPM consider specialized laboratory-grade flowmeters.

Pros & Cons

Pros

• Solid build quality with eco-brass main case and corrosion-resistant wetted parts.
• Good accuracy for the price, with 1.5% error in normal flow ranges and usable low-flow performance.
• Easy installation with 3/4' NPT couplings and a pulse output that integrates with loggers or counters.
• Serviceable inlet filter that can be cleaned without breaking the metrological seal.

Cons

• Not specified as lead-free, so it may not meet all potable water regulations in some jurisdictions.
• Designed for cold water; users needing certified hot-water performance should choose a different model.

Specifications

Meter size	DN20 (5/8 x 3/4)
Connection	3/4' NPT couplings
Units	Gallon
Accuracy	Normal flow 1.5%, Low flow 3%
Flow range	Min 0.25 GPM, Continues 10 GPM, High 20 GPM
Body material	Eco-brass alloy with composite components
Output	Pulse output for remote monitoring

Our Verdict

The Watflow DN20 is a pragmatic, value-oriented cold water meter that suits installers and small facilities needing an accurate gallon-based meter with pulse output. It trades premium certification for solid materials and serviceable design, making it a strong choice where corrosion resistance, ease of installation, and pulse monitoring are priorities.

Frequently Asked Questions

Is this meter suitable for potable water?
The meter is made from eco-brass alloy and corrosion-resistant materials but is specified as not lead-free, so check local potable water regulations before use.

Can I connect it to a data logger?
Yes, the meter includes a pulse output designed to interface with counters and data loggers for remote monitoring.

What is the minimum flow rate it measures reliably?
The minimum flow rate is 0.25 GPM, with a low-flow accuracy of about 3%.