--- title: How to Read a Dewatering Pump Performance Curve Before Buying date: 2026-08-13T06:37:41Z modified: 2026-08-31T06:55:57Z permalink: "https://www.defucc.com/blog/buying-guide/dewatering-pump-curve/" type: post status: publish excerpt: "" wpid: 2861 categories: - buying guide featured_image: "https://www.defucc.com/wp-content/uploads/2026/08/image-10.webp" featured_image_alt: How to Read a Dewatering Pump Performance Curve timestamp: 2026-08-31T06:55:57Z tags: - buying guide --- ## **Quick Answer:** A pump curve shows how much head a pump can produce at different flow rates. Start with the flow you need on the horizontal axis, trace upward to the pump curve, and read the corresponding head on the vertical axis. Then check the efficiency lines and how close that operating point is to the pump’s BEP. ## **What Does a Pump Performance Curve Show?** A pump performance curve shows how a pump’s flow and head change in relation to each other. The m³/h, GPM, or L/s on the horizontal axis typically shows the flow. Meanwhile, the head appears in feet or meters on the vertical axis. You’ll see the curve sloping downwards from left to right. That implies the pump produces less head at higher flow rates and more head as the flow decreases. Let’s say a curve shows 22 meters of head at 200 m³/h and 30 meters of head at 100 m³/h. Now, if the required operating point is around 200 m³/h, what matters more is the first operating point. The maximum head of the pump can’t indicate whether it can meet your criteria at the flow you require. ## **How Do You Read Flow and Head on a Pump Curve?** Start with the required flow on the horizontal axis. Move straight up until you reach the pump’s head curve, then move horizontally to the vertical axis. The value there is the head the pump can produce at that flow. You can reverse the process when you already know the required head. Start on the vertical axis, move across to the curve, and then drop down to see the corresponding flow. The key is to read the two values at the same point on the curve. A pump might list a maximum flow of 300 m³/h and a maximum head of 40 meters, for example, but that doesn’t mean it can deliver 300 m³/h at 40 meters. Those maximum values normally occur at different points. ## **What Does Efficiency Mean on a Pump Curve?** Efficiency shows how effectively the pump converts input power into useful hydraulic output. On many curves, you’ll see efficiency shown as percentage lines or contours across the operating range. Higher efficiency means less of the input energy is being lost inside the pump. But don’t pick the highest percentage you can find without looking at where it occurs. What matters is whether your required flow and head place the pump in an efficient part of its operating range. If your operating point sits well away from the higher-efficiency area, the pump may still move the water, but it may use more energy and experience greater mechanical stress over time. ## **What Is the Best Efficiency Point on a Pump?** The pump BEP, or Best Efficiency Point, is the point on the curve where the pump operates at its highest hydraulic efficiency. It is generally the preferred area for continuous operation because hydraulic forces are better balanced there. You don’t need the operating point to land exactly on the BEP. The recommended range around it varies by pump design, so there isn’t one percentage that applies to every [centrifugal pump](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/taxonomy/product_cat/centrifugal-pump.md). When comparing pumps, look at where your required flow and head fall relative to the best efficiency point pump manufacturers provide. An operating point reasonably close to the BEP and within the manufacturer’s recommended operating region is generally preferable to one near either extreme of the curve. ## **What Should You Check on a Pump Curve Before Buying?** The first step is to locate the point where your head and required flow meet. This point has to sit on the pump’s published curve instead of beyond its operating range. The second is to check the efficiency at that point and its position relative to the BEP. Even if the pump technically meets your head and flow requirements, it can still be a misfit if the operating point falls far from its efficient operating area. Also make sure you’re reading the right curve. Manufacturers may publish different curves for changes in pump size, impeller diameter, or rotational speed. The model and configuration shown on the chart need to match the pump you’re actually considering. DEFU can provide the relevant performance data for a customer’s required operating conditions. [Our dewatering pumps](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/page/types-of-dewatering-pumps.md) are tested according to [ISO 9906](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/post/the-importance-of-iso-9906-certification-in-pump-selection.md), which sets procedures and acceptance criteria for hydraulic performance testing of rotodynamic pumps. This gives buyers a tested basis for comparing published flow, head, and efficiency data rather than relying only on nominal specifications. MP Series Vacuum Assisted Dry Priming Slurry Dewatering Pump High-performance solution for the most demanding dewatering tasks in mining, offering unmatched efficiency and reliability. [Explore Mine-Dewatering Pumps](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/page/mine-dewatering-pump-manufacturer.md) [ ![DEFUC IHF Chemical Centrifugal Pump](https://www.defucc.com/wp-content/uploads/2025/05/MP-800x800.jpg) ](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/page/mine-dewatering-pump-manufacturer.md) ## **How Can You Compare Two Pump Curves?** Compare both pumps at the same required flow and head, rather than comparing their maximum specifications. Then look at the efficiency and BEP position at that operating point. Suppose two pumps can both reach your required point. Pump A reaches it near its BEP, while Pump B reaches it much farther along the curve. Pump A would generally be the stronger candidate from a hydraulic efficiency and operating-stability standpoint. That is why reading the full curve matters before buying a dewatering pump. A specification sheet can tell you what a pump can reach. The curve tells you how it is expected to perform at the conditions where you’ll actually run it. [Get Free Quote](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/page/contact.md) Welcome to Our Blog! Professional Dewatering Pump Manufacturer Written by the Engineering & Solutions Team at WENZHOU DEFU MACHINERY CO., LTD. Backed by 3 manufacturing bases and over 10 years of expertise as a leading dewatering pump manufacturer, our team is dedicated to sharing practical dewatering pump insights and engineered fluid handling solutions for global projects. [ Contact Us → ](https://www.defucc.com/wp-content/uploads/wp-mfa-exports/page/contact.md) ![WENZHOU DEFU MACHINERY CO., LTD. - Dewatering Pump Manufacturer](https://defucc.b-cdn.net/wp-content/uploads/2025/06/2-1-1--768x534.jpg)