How do I drain and clean a hot tub?

Jacuzzi's guidance is to drain "every 3-4 months for chlorine/bromine systems or annually for salt water systems." Drain sooner if the water is cloudy, smells bad or foams and chemicals do not fix it. Jacuzzi also suggests more frequent draining after heavy use such as parties.

• Cut the power at the breaker. Jacuzzi says running pumps or heaters while the water level drops below the intake points can cause serious damage.
• Let the water cool below 100 degrees. Jacuzzi's reasoning is burn risk at the hose connection and stress on plastic parts.
• Gather a hose and, if you have one, a submersible pump. Jacuzzi recommends a 3/4-inch hose over 5/8-inch for faster flow, and says a pump cuts a 400 to 500 gallon spa from 45 to 90 minutes down to 10 to 15.
• Pick the discharge point first. See the next section.

Spa water carries chlorine or bromine, so it does not belong in the street or a wash. City of Phoenix Water Services lists the do's and don'ts for pool discharge, and the same chemically treated water in a hot tub follows the same logic: send it to the sanitary sewer cleanout, or onto tolerant plants on your own property. The flyer says "Don't backwash or drain your pool into the street," "Don't drain into a septic tank," and warns against installing a pool drain line "as a permanent fixture." The Phoenix cleanout steps are in our guide to legally draining or backwashing a pool in Phoenix.

Two practical points from the city flyer. First, the maximum recommended discharge rate into a cleanout is 12 gallons per minute. At that rate a 400 to 500 gallon tub takes roughly 35 to 40 minutes, so a gravity spigot and a small pump both work; do not point a big pump at the cleanout. Second, check for backups right away. The flyer says drains in showers and tubs "are the first places to check," and if water backs up, turn off the pump immediately because "you may have a blockage, or the flow rate is too high." A cleanout that backs up at a low flow rate is telling you the sewer line needs attention, which is a drain cleaning or camera inspection job, not a hot tub problem.

If you drain to landscape instead, remember the city's caution that pool water "contains chlorine and salt which can harm certain plants." Other cities set their own rules. Chandler, for example, says it "prefers that all pool and spa water discharges be maintained on private property or in the sanitary sewer cleanout." Check your city before you pull the plug.

1. 1Open the drain valve. Jacuzzi describes a spigot at the base of the cabinet behind a removable panel. Thread the hose on without overtightening, since "Most drain valve threads are plastic and can crack under excessive force."
2. 2Or use the pump. Set it in the deepest part of the shell. Jacuzzi says to turn it off the moment the water drops below the intake to avoid running it dry, and that the last inch usually needs towels or a shop vacuum.
3. 3Open any second drain point. Some models have more than one, and Jacuzzi says opening them together improves flow.

• Plumbing lines. Jacuzzi says to run a line flush product before the final drain "to remove biofilm and bacteria from internal pipes." Do this before you pull the water, not after.
• Shell. Use a cleaner made for acrylic or vinyl. Jacuzzi also gives a gentle mix of 4 parts warm water to 1 part white vinegar. Skip household cleaners, which can foam or leave residue.
• Filter. Rinse it with a garden hose, then soak it in filter cleaner. Jacuzzi's setup guide warns against a pressure washer, which can damage the media, and says to replace cartridges every 3 to 4 months under normal use.
• Cover, gaskets and visible fittings. This is the one time everything is accessible.

Fill through the filter well with the hose, slowly, so air is not pulled into the plumbing. Jacuzzi says rapid filling can trap bubbles and cause pump cavitation. Its setup guide also recommends a hose filter on the fill hose to remove chloramines, metals and minerals. If the jets run weak after you refill, the likely cause is an airlock. Cycling the pumps on and off usually clears it, per Jacuzzi.

Phoenix fill water is hard. The city's water quality report lists total hardness of 172 to 302 ppm, or 10 to 17.6 grains per gallon. Jacuzzi's target for calcium hardness is 150 to 250 ppm. Calcium is only part of total hardness, so test your fill water before you add any calcium increaser. Scale shows up as chalky film on the waterline and inside the heater. Then balance alkalinity first, then pH, then sanitizer, as Jacuzzi lays out.

The tub itself is the manufacturer's or a spa technician's job. Call a plumber when the water you are draining backs up inside the house, when your sewer cleanout cap is seized or buried, when a hose bib will not shut off or leaks at the handle (how to replace an outdoor faucet), or when you want a vacuum breaker on the fill hose bib. HQ Plumbing and Air handles those household plumbing pieces through residential plumbing service, with a firm price before work starts.