How water hardness changes the effect of detergent
Short answer: Hard water contains lime, and the lime binds part of the detergent before it reaches the clothes. That is why more detergent is needed for the same cleaning. Your water company can tell you how hard your water is, and the pack shows how to dose for it.
Lime uses up the detergent
Hard water contains dissolved lime, and the lime binds part of the detergent before it can work on the clothes. That part goes to holding the lime back instead of loosening dirt. The result is that the same amount of detergent cleans worse in hard water than in soft water.
The dose depends on hardness
The detergent pack lists different amounts for soft, medium and hard water. Follow the amount that suits your area instead of using the same measure every time. The same thinking applies to caring for a bamboo dressing gown for men, which washes better when detergent and water match.
Lime settles in the fibres
Over time, lime settles in the fabric and makes it stiffer and less absorbent. You notice it most on towels, but also on soft everyday clothes. Grey deposits can come from lime rather than dirt. See sleepwear and Nordic Weaving for more clothes that need gentle washing.
How to find your hardness
Your water company states the hardness in your area, and the figure is often on the water bill or on their website. Hardness is measured in degrees, and the scale runs from soft to very hard. With the figure you can read off the right dose on the pack. It takes a few minutes and can save detergent.
Hard water and white clothes
Lime can give white clothes a greyish tone, because deposits hold on to dirt and make the fibres look duller. More detergent is not always the answer, since any excess stays in the fabric. Set the dose to the hardness first, and wash a little hotter if the item allows it. Always follow the care label.
Soft water needs less
With soft water you need less detergent, and it is easy to overdose. Too much is rinsed out poorly and leaves clothes stiff. Start with the lowest amount the pack gives for soft water and see whether the clothes come out clean. It is better to add a little more next time than to use too much every time.
The water affects the machine too
Lime does not only settle in clothes, but also in the heating element and hoses of the machine. That can make it use more energy and heat the water less evenly. The right dose helps in both cases, and an empty wash at high temperature now and then keeps the drum cleaner. Follow your machine's own instructions.
What helps in daily life
Measure the detergent instead of pouring by eye, and use the dose for your water. Choose a programme with enough rinses so that leftover detergent comes out. Dry clothes in the air when you can, since that is gentler on the fabric. Small habits like these give softer clothes and a machine that lasts longer.
Washing soft everyday clothes
Soft clothes for the night and for home need a gentle wash, and water hardness affects the result. Wash at a low temperature, choose detergent without excess and avoid filling the machine completely. That gives the fabric room to rinse clean and helps you avoid stiff deposits. Read the care label in the garment before you choose a programme.
Frequently asked questions
How do I find my water hardness?
Your water company states the hardness, and it is often on your water bill or on their website. You then use that figure to choose the right detergent dose from the pack, so you use neither too little nor too much.
Does descaler help?
It can help the machine, but the right detergent dose matters more for the clothes. Descaler removes lime inside the machine, yet it does not change how much detergent your water needs, so keep following the pack.
Is soft water always better?
For washing, yes. It needs less detergent, and clothes come out softer because no lime settles in the fibres. It is easy to overdose in soft water though, so measure the detergent by the pack.
You can find the full range at Bamboo-Clothing.com.
