Soft top drains

Every Miata soft top drains rain through tubes that run down inside the car, and the tubes clog. Unlike most topics in this section, the fix is mostly cleaning, not buying. This page says where owners say the drains are, how they clear them, and what little is sold for the job. It is not a repair guide.

How to read it. The owner accounts are from Miata.net forum threads I read on 1 October 2026, dated below. They are individual owners' experience, not tested by me, and posters sometimes disagree. There are no prices on this page.

NA and NB: what owners say

From a May 2013 thread with photographs (NA and NB, 1990-2005):

• Where. The tops of the two main drains are behind the seat belt towers; you lift the front of the carpet behind each tower to see the hole. The bottoms are under the car in front of each rear tire, a tube cut at a slant with a one-way flap on it.
• The tool. The poster used a trumpet brush (a trombone brush is the same idea), which he said costs a few dollars at a music store or online. His method for badly clogged drains: a helper holds a shop vacuum at the top of the drain while he pushes the brush up from the bottom, which kept it from getting messy. Other posters used a car antenna mast or a spare oil dipstick.
• What came out. Several posters found years of mud, leaves and debris, and the original poster found moss growing on the rear carpet near his drains. He also said the drain tubes can be pushed off the plastic fittings at the top, and that putting them back is not pleasant.
• One that would not clear. A poster with a blockage about 14 to 16 inches down got only some debris out with a trombone brush and a coat hanger, from either end; the thread does not say how it ended.
• Other drains the thread adds. A drain under the fuel filler lid, which one poster found packed solid. The drains in the windshield header, in the weatherstrip at the top of each "ear"; one poster says they need a long brush, or a piece of coaxial cable with silicone on the end, and that clogged ones soak the front carpets and can lead to rust in the floor. The drain channels under the hood, where one poster suggested lightly stuffing the holes with plastic dish scrubbing pads to trap debris. Four small drain holes in each rocker panel, near the jacking points, which a poster says can be opened with a large screwdriver or awl. The air-conditioning drain tray under the dash, a possible cause of water in the passenger footwell.

ND: what owners say

From a December 2019 to July 2020 thread on a flooded passenger side:

• Filters. On the ND the top drains have foam filter baskets behind the seats, reached by removing interior trim. One poster's flood was not a clog: he had not seated the driver's side filter correctly after cleaning it.
• Below the filters. A poster advised feeding a trombone brush down through the drain and pulling it out from underneath the car, not pushing it down and pulling it back up, which could damage the one-way flap at the bottom. Another poster, whose filters were clear, found a wad of debris plugging the drains lower down when he had the covers off while fitting a roll bar. Another poster shared illustrations from the factory manual, and a poster linked a video, showing a cleaning hole behind and below the seat belt retractor; the poster with the illustrations noted that the hole in the video is in a part above the drain tray.
• How to test. A poster suggested pouring a measured amount of water in and collecting it at the outlet to see whether any is missing.
• A design complaint. One owner, testing a new car, saw water leak around the seal of the filter basket when he poured water in with the top partly down, and concluded the system is poorly designed. Another owner saw the same on a washed car. That is two owners' observation, not Mazda's statement.
• Cost. A UK owner in the thread had been told Mazda would replace the whole drain system, and chose to try a cleaning wire first.

What is sold

• NC (2006-2015) drain repair kit. mazdaparts.org, a Mazda parts retailer, lists a "Top Drain Repair Kit" (part MIATADRAIN) for 2006-2015 cars with a folding soft top. It says drains clogged with leaves and debris can let water collect in the footwells, and that the kit supplies updated parts. The page does not list what is in the kit; installation instructions are a separate PDF.
• Brushes. The threads point owners to a trumpet or trombone cleaning brush, available at music stores. I did not find a Miata seller that sells one that I could open.

Not covered yet

• Replacement drain tubes or flaps for the NA and NB, and any ND parts. I looked at the NC kit only.
• The videos the ND thread links; I did not watch them.
• Whether Mazda's NC kit is the same as the revised drains owners mention; the seller's page does not say.

© 2026 Fischer Interactive LLC. Written for the Ref Sensor app's Miata users. The seller's page is the authority.