Why Regular Water Changes Matter
Even with perfect chemical maintenance, your hot tub water eventually reaches a point where it simply cannot be balanced effectively. Total dissolved solids accumulate over time from body oils, lotions, sweat, and the chemicals themselves, creating water that looks dull, feels different, and resists proper treatment. Understanding when and how to drain your spa ensures you always enjoy the freshest, most inviting water possible.
Most manufacturers recommend draining and refilling every three to four months, though heavy use may require more frequent changes. Some owners stretch intervals to six months with light usage and excellent maintenance, but waiting too long creates problems that fresh water easily prevents. Think of draining as hitting the reset button on your water chemistry—a clean slate that makes ongoing maintenance simpler and more effective.
Signs Your Hot Tub Needs Draining
Beyond the calendar, several indicators suggest your water needs changing. Persistent cloudiness that won't clear despite proper chemical treatment often signals high total dissolved solids. Foam that forms when jets activate and doesn't dissipate quickly indicates accumulated surfactants from soaps, lotions, and body products. Water that feels slippery or has an unusual odor despite adequate sanitizer levels needs replacement.
Difficulty maintaining chemical balance provides another clear signal. When you find yourself adding increasing amounts of chemicals to achieve the same results, or when pH and alkalinity swing wildly despite careful adjustment, your water has reached the end of its useful life. Fighting this battle wastes money on chemicals and time on testing while never achieving satisfying results—fresh water solves the problem immediately.
Preparing to Drain Your Spa
Before draining, run a line flush product through your system to clean biofilm and buildup from the plumbing. These products break down organic accumulation inside pipes that regular water circulation doesn't remove. Add the flush product according to package directions, run all jets on high for the specified time, and you'll likely see debris emerge into the water—proof the product is working.
Plan your drainage destination carefully. Most municipalities prohibit draining chemically treated water directly into storm drains due to environmental concerns. Acceptable options typically include sanitary sewer cleanouts, landscaped areas where the volume can absorb without runoff, or professional pump-out services. Allow chlorine or bromine levels to drop before draining onto vegetation to prevent plant damage.
The Draining Process
Most hot tubs include a drain valve near the base of the cabinet, often with a hose attachment fitting. Connect a standard garden hose and route it to your chosen drainage location. Open the valve and gravity will do the work, though complete drainage takes one to three hours depending on your spa's size and the hose routing. Some owners use submersible pumps to accelerate the process significantly.
Once the main volume drains, use a wet-dry vacuum to remove remaining water from the footwell, seats, and jet housings. This standing water harbors bacteria and will contaminate your fresh fill if left behind. Pay special attention to any low spots where water pools. Remove and clean your filter cartridges during this process, or install fresh filters if replacement is due.
Cleaning the Empty Shell
With the spa empty, you have perfect access for thorough cleaning. Use a non-abrasive spa surface cleaner and soft cloth to wipe down the entire shell, paying attention to the waterline where oils and minerals accumulate. Clean jet faces, headrests, and any removable pillows. Inspect the shell for any cracks, scratches, or damage that might need attention.
Rinse the shell thoroughly to remove all cleaning product residue, which can cause foaming when you refill. A final wipe with clean water ensures no chemical traces remain. This is also an excellent time to inspect and clean the cabinet interior, check equipment connections, and address any maintenance items that are difficult to reach when the spa is full.
Refilling Your Hot Tub
Place your garden hose directly into the filter housing or skimmer rather than simply filling from the top of the spa. This technique forces water through the plumbing system first, pushing air out and preventing airlocks that can damage pumps or prevent proper circulation. Fill until water reaches the middle of the skimmer opening or the level recommended in your owner's manual.
If your source water is particularly hard or contains high metal content, consider using a hose-end pre-filter during filling. These inexpensive devices remove minerals, metals, and sediment before water enters your spa, giving you a cleaner starting point for chemical treatment. The investment saves time and chemicals while producing better water quality from the start.
Initial Chemical Treatment
Fresh water requires careful initial treatment to establish proper balance. Start by testing pH, alkalinity, and calcium hardness before adding any chemicals. Adjust alkalinity first, as it affects pH stability. Once alkalinity reaches the target range of 80 to 120 parts per million, adjust pH to between 7.2 and 7.8. Finally, address calcium hardness if your source water falls outside the 150 to 250 ppm ideal range.
With balance established, add your sanitizer to reach the appropriate level for your chosen system. Run the circulation system for at least an hour to distribute chemicals thoroughly, then retest and adjust as needed. Allow the water to heat to operating temperature before the final round of testing, as temperature affects chemical behavior and test accuracy.
Breaking In New Water
Fresh water often behaves differently than established water during the first few days. You may notice more rapid pH drift, unusual foam, or cloudiness as the water adjusts. Test more frequently during this break-in period—daily testing for the first week helps you understand how your specific water source responds to treatment and identify any issues early.
Some spa owners perform an initial shock treatment after the water reaches temperature to oxidize any contaminants introduced during filling. Others wait a few days to see how the water stabilizes first. Either approach works; the key is monitoring closely and responding promptly to any readings outside the target range. Within a week, your fresh water should settle into predictable behavior.
Extending Time Between Drains
Several practices help maximize the useful life of your water between changes. Shower before soaking to remove lotions, deodorants, and other products that contaminate water. Keep hair tied up or wear a cap to reduce hair product introduction. Enforce a no-food-or-drink policy in the spa, or at least prohibit anything that might spill.
Regular shocking oxidizes organic contaminants before they accumulate to problematic levels. Consistent filter cleaning prevents debris from cycling back into the water. Keeping the cover on when the spa isn't in use reduces evaporation that concentrates dissolved solids and prevents airborne debris from entering. These simple habits dramatically extend water life while maintaining superior quality throughout the interval.