The chemistry, briefly, because it explains the rest
Fats and oils entering a drain meet water carrying dissolved calcium and magnesium. They react, and the product is an insoluble metallic soap — the same reaction that produces bathroom soap scum, running at commercial scale.
That deposit is harder, more adherent and less soluble than grease on its own. Hot water and detergent, which will at least temporarily mobilise plain grease, have far less effect on it.
At the mineral concentrations found here — among the hardest in Texas — the effect is significant rather than academic. A kitchen that would need drain attention twice a year elsewhere may need it quarterly here.
It also means the deposit builds on the pipe wall rather than passing through as particles, narrowing the line steadily until the day it stops.
Worth knowing
This is the practical case for treating the water as well as maintaining the drains. Softening does not remove grease, but it removes the mineral half of the reaction — so what does accumulate stays softer and clears more easily. See commercial hard water.
Why jetting rather than snaking
This distinction matters more in a commercial kitchen than anywhere else, and it is the most common reason a line that was “just cleared” blocks again within weeks.
An auger punches a hole through the blockage. Flow returns immediately, which feels like success. But the deposit is still on the pipe wall, and the hole is the only clear path — so material starts catching on the surrounding buildup straight away.
Jetting scours the wall. High-pressure water directed backwards along the pipe cuts the accumulated deposit off the surface and flushes it out, returning the line to something close to its full internal diameter.
In a grease environment the difference in how long the result lasts is substantial — weeks against months.
Jetting needs a pipe sound enough to take the pressure, which is why a camera inspection is worth running first on an older line. It also needs somewhere for the debris to go, which is the grease trap's job.
The grease trap
The trap is what stops the problem becoming the municipality's, and it is generally where compliance obligations sit.
It works by residence time. Wastewater slows enough for fats to rise and solids to settle, so what leaves is comparatively clean. Overload it — too much volume too fast — and the separation does not happen, so grease passes straight through as if the trap were not there.
The 25% rule is the common standard: service when fats and solids reach roughly a quarter of the trap's capacity. Beyond that, efficiency falls sharply.
Keep the records. Most jurisdictions require documented pumping and servicing, and the paperwork is what an inspection asks for. It is also what defends you if a downstream problem is attributed to your premises.
Undersized traps are common in premises that changed use or expanded without the plumbing being reassessed. If yours needs servicing far more often than expected, capacity is the first thing to check — not the schedule.
Daily and weekly practice
The maintenance schedule matters, but most of the load is decided by what happens at the sink during service.
- Scrape and wipe before washing. Every gram of fat that reaches the drain is a gram the trap has to catch. This is the single highest-value habit and it is entirely about staff practice.
- Fryer oil goes to the collection container, never down any drain, in any quantity, ever.
- Fit and clean strainers on every sink and floor drain, daily.
- Cold water at the disposal, not hot — hot water melts fat so it flows past and re-solidifies further down the line where nobody can reach it.
- Flush floor drains regularly, including in areas that see little use. Dry traps let sewer gas into the kitchen, which is both unpleasant and a health inspection issue.
- Brief new staff on it. Turnover is why drain practice degrades, and a kitchen's drain performance tracks staff habits more closely than its service schedule.
Building a schedule that holds
Start with a camera survey of the kitchen's drainage. It establishes pipe material and condition, finds sags and existing buildup, and gives you a baseline. On an older Boerne property that survey often explains a problem everyone assumed was operational.
Set a jetting interval from your actual volume, not a generic figure. High-volume kitchens on this water commonly need quarterly; lighter operations twice a year.
Schedule around service. Drain work during trading hours is disruptive and rushed; booked into a closure or a quiet morning it is neither.
Log everything — jetting, trap servicing, camera surveys, blockages and their causes. Over a year the pattern tells you whether you have a maintenance issue or a structural one, and if the same section blocks repeatedly, that is a pipe problem rather than a grease problem.
The alternative is emergency work, which arrives on a Friday evening, costs the premium rate, and closes the kitchen.