Descaling a dishwasher is important if you want to keep it working as efficiently and effectively as possible. Limescale builds up quickly in dishwashers that are used regularly, especially in areas with hard tap water. You need to descale your dishwasher regularly to ensure that your dishes come out clean.

A dishwasher filter should be replaced every five years, depending on the manufacturer's recommendations and the frequency of use. The exact timing can vary based on factors such as the hardness of your water, how well you rinse dishes before loading them, and how often you clean the filter. Regularly inspect the filter for signs of wear and tear or damage. If the filter appears worn out, damaged, or excessively clogged despite regular cleaning, it should be replaced sooner.

Yes, a dishwasher needs an air gap to prevent backflow. Additionally, in many locations, air gaps or another measure to prevent backflow are required for building code compliance. There are alternatives to an air gap, like a Studor vent or a loop and trap design, but an air gap is the simplest and most popular solution.  

You should avoid using a pressure washer on any surface or item that could be damaged by the high-pressure spray, as some materials are too delicate to withstand the force.

Key items and surfaces to avoid include:

• Electrical Components: Never pressure wash electrical systems, as water can cause short-circuits and create a safety hazard. This includes utility meters, breaker boxes, electrical outlets, generators, and HVAC or air conditioner units.

• Delicate and Fragile Materials: Fragile items can crack, shatter, or be stripped by the pressure. Avoid pressure washing windows, glass, light fixtures, shingled roofs (especially asphalt), and stucco.

• Painted, Stained, or Sealed Surfaces: Unless your goal is to strip the finish, do not pressure wash painted surfaces, stained wood (like decks), or anything with a protective seal that could be stripped away. Be especially cautious with older surfaces that may contain lead paint.

• Soft Woods and Certain Decking: Delicate surfaces like softwood, composite decking, and antique or wooden patio furniture can be etched or damaged. If you must wash wood, use a lower-powered pressure washer with a wide-angle nozzle to prevent damage.

• Living Things: Never use a pressure washer on people, pets, or plants. The force can cause serious injury and will destroy landscaping.