The seawater encroachment is a problem of water quality.

海水入侵是一个水质问题。

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However, the heater has the problems such as small flow and difficult heating owing to the problem of water quality when the period of use becomes longer.

但是因为水质的问题，随着使用时间的变长，热水器会出现流量变小、加热困难等问题。

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The water damage of bituminous pavement is a general quality problem of highway engineering.

沥青路面水损害问题是公路工程质量通病之一。

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But Dr Baretta warns that the jetties proposed along with the gates will be a problem reducing flushing of the lagoon, and thus its water quality.

ECONOMIST: Flood barriers

On the water front, not only is dirty quality still a big problem in much of Asia, but scarce quantity, too.

FORBES: Asia's Latest Reminders of Its Ecological Fix